Rockets fired from Lebanon late Sunday exploded in the Israeli towns of Upper Nazareth and Afula, the Israeli military said, but no casualties were reported.

The barrage showed, however, that Hezbollah forces could range farther south than previously shown and sparked talk of whether the forces based in Lebanon can reach places like Tel Aviv.

The two towns are about 25 miles south of the Lebanese border, about the same distance as Haifa, which was hit earlier today with a rocket that killed eight people.

Just prior to the rocket fire, for the fourth time since Wednesday an Israeli warship blasted Beirut's Rafik Hariri International Airport. Security officials reported that four missiles bombarded the area, setting a fuel storage tank ablaze.

The airport has been closed since an Israeli aircraft fired missiles at the runways on Wednesday. Air raids have ignited the airport's fuel storage tanks twice since the Israeli strikes on Lebanon began. Last Friday warplanes blasted runways, setting fuel storage tanks on fire.

Israel imposed an air and sea blockade on Lebanon in an attempt to force Hezbollah to free two captured Israeli soldiers. Israel also struck roads, bridges and army bases, knocking out electricity in large parts of the capital.

The U.S. Marines on Sunday evacuated from Lebanon 20 Americans with pre-existing medical conditions after guerrillas pounded the northern Israeli city of Haifa, killing eight people at a train station and wounding seven others.

Within two hours of the 8 a.m. Haifa attack, Israeli warplanes struck back with a hit on Hezbollah's south Beirut headquarters, and hours later Lebanese security officials said an Israeli airstrike on the southern port city of Tyre had killed nine civilians and wounded 42.

Hezbollah's leader also appeared on TV for the first time since Israel intensified airstrikes five days ago, saying, "We are determined and will be victorious."

And Israeli Prime Minister Ehud Olmert vowed that there would be "far-reaching consequences" for Hezbollah's deadliest strike ever on Israel.

In Russia, German Chancellor Angela Merkel said the leaders of the Group of Eight had agreed on a joint statement calling for the abducted Israeli soldiers to be freed, for the attacks on Israel to stop and for Israel to end its military action.

"It is a strong message with a clear political content," Merkel told reporters.

She said the statement also expresses support for the Lebanese government, she said.

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Hezbollah sent at least 20 rockets into Haifa after Israel launched its fiercest bombardment of the Lebanese capital after midnight on Saturday. The attack, which marked a continuing increase in violence after five days of back-and-forth attacks, flattened Beirut apartment buildings and knocked out power around the city.

Planning and assessment teams arrived at the U.S. Embassy in Aukar to arrange transportation for Americans wishing to leave.

"The arrival of the teams is an important first step in facilitating the safe departure of Americans who want to leave Lebanon," according to the U.S. Embassy Web site.

The 20 evacuated American citizens were being flown to Cyprus, where it was expected they would connect with commercial flights.

Shortly after, the State Department issued a message to Americans in Lebanon, telling them to stay put as the avenues for egress had become too dangerous.

"It is too perilous to try to make your way out of Lebanon," the statement read, with one official pointing out that some routes would coincide with anti-American demonstrations planned for Monday in Syria, which supports Hezbollah.

"They don't want American citizens heading into such an environment," said Amb. Jim Jeffrey, principal deputy assistant secretary for near-East affairs.

“We have been told to stay in the hotel … and not to venture out into the street,” the Rev. Lawrence Biondi told FOX News from Lebanon, where he was to give a commencement speech with a fellow clergy member.

“Now I know how terrible it is to be a hostage.”

The State Department was urging Americans to register with the Embassy at travel.state.gov so the U.S. government can e-mail them evacuation updates and keep track of them.

About 25,000 Americans live or work in Lebanon.

"We obviously have plans and contingency plans should we need to bring people out," Secretary of State Condoleezza Rice told reporters at the Group of Eight summit in Russia. "I get reports on this every couple of hours as to how this is going. Our ambassador who is on the ground will obviously do what we need to protect Americans."

About 350 people — most of them Europeans — were evacuated Saturday night and early Sunday from Lebanon to Cyprus on Italian military flights.

CountryWatch: Lebanon

CountryWatch: Israel

Israeli airstrikes have closed down Beirut's international airport and targeted the main highway to neighboring Syria. Israel also imposed a naval blockade on Lebanon.

Hezbollah leader Sheik Hassan Nasrallah made his first televised appearance to address the conflict, claiming Israel's attacks focused on civilian targets.

"We are trying to concentrate only on military targets, to hold our anger and not retaliate," Nasrallah said.

"We want to get rid of their arrogance," he continued. "The enemy knows nothing of our power."

Israeli authorities warned all residents in the central city of Tel Aviv and north to be on heightened alert, reflecting the longer range of the missile attacks.

Smoke rose over Haifa and air raid sirens wailed as the dead and wounded were evacuated. Other rockets hit the city's major oil refinery, gas storage tanks and a major street during the busy morning rush hour.

Israeli officials blamed Syria and Iran for providing the weaponry that hit Haifa — raising the specter of a wider regional confrontation.

The Israeli air force dropped leaflets over south Lebanon telling residents to leave immediately before an imminent attack.

"In two or three hours we are going to attack the south of Lebanon heavily," said Maj. Gen. Udi Adam, the head of Israel's northern command.

Police and residents in Lebanon said 41 people died in the past 24 hours, nearly all civilians, raising to 148 the five-day death toll in the country. In Israel, 24 have died, half of them civilians.

Sunday brought the fiercest attacks since the conflict erupted Wednesday after Hezbollah guerrillas penetrated Israel in brazen raid, killing eight soldiers and capturing another two.

The fighting opened a second front for Israel, which had already been fighting Hamas-linked militants in the Gaza Strip following the capture of another Israeli soldier on June 25.

Israeli troops, tanks and helicopter gunships re-entered northern Gaza on Sunday, firing missiles and exchanging gunfire with armed Palestinians in a raid that killed three militants.

Masked militants in Gaza vowed in a news conference Sunday to launch more rockets at Israel "to show solidarity with the twin of our resistance," referring to Hezbollah.

Israel has expanded its mission from the immediate need to free the three soldiers to a campaign to halt rocket fire from Gaza and to neutralize Hezbollah in Lebanon. Iran and Syria are prime supporters of the two Islamic militant groups, raising fears they could be drawn into a regional war.

Syrian Information Minister Mohsen Bilal warned that any aggression against it "will be met with a firm and direct response whose timing and methods are unlimited."

Israeli officials said the guerrillas, who had been firing relatively small Katyusha rockets, launched at least four Iranian-made Fajr missile at Haifa. Those missiles, with a range of 28 miles, have a far larger warhead than the Katyushas. Adam, the head of Israel's northern command, confirmed that Iranian-made missiles were fired at Haifa — the first time Hezbollah had used the Fajr missiles in attacking Israel.

Shaul Mofaz, an Israeli Cabinet minister and former army chief of staff, pointed his fingers at Syria.

"The ammunition that Hezbollah used this morning ... is Syrian ammunition," he said. He also compared Hezbollah to Al Qaeda, saying Israel should mount its operation accordingly.

Hezbollah guerrillas said they hit Haifa, Israel's third-largest city, with dozens of Raad-2 and Raad-3 missiles. The attack was certain to invite harsh Israeli retaliation.

"Nothing will deter us," Olmert said at the beginning of his government's weekly Cabinet meeting. "There will be far-reaching consequences in our relations on the northern border and in the area in general."

At least 20 rockets slammed into Haifa on Sunday, and one of them hit a section of the train depot where crews perform maintenance on the trains, tearing a huge hole in the roof and killing eight people. One body was covered in a white bag and placed on a stretcher on the ground.

"I saw bodies in the warehouse. The picture was not pleasant," one witness, who identified himself as Igor, told Israel's Army Radio.

About 30 people were working in the depot at the time of the attack, Ofer Litzevski, an official with the train company, told reporters.

Mayor Yona Yahav warned people against holding large gatherings and canceled all cultural events in the city. Trains in northern Israel were halted and bus service in Haifa and north was stopped.

Hezbollah said it intentionally avoided hitting petrochemical installations in Haifa, according to a statement read on Al-Manar.

"But the next time, it [Hezbollah] will not spare anything in Haifa and its surroundings," the statement said.

Israel deployed a Patriot missile battery in Haifa on Saturday to protect the city against surface-to-surface missiles. But the Patriot was not built to combat the kind of missiles that hit Haifa on Sunday, said Brig. Gen. Ido Nehushtan, a member of the army's General Staff.

Rockets fired by Lebanese militants also hit Acco, Nahariya and several other northern towns, and residents of the region were told to head to bomb shelters. Israeli rescue teams said 20 people were injured in Haifa and Acco, four of them seriously.

During Israel's overnight attacks on Lebanon, Al-Manar television, Hezbollah's main voice to the world, was briefly knocked off the air. The Jiyeh power plant, on the southern outskirts, was in flames after being hit, cutting electricity to many areas in the capital and south Lebanon.

Large swaths of the capital were covered in fine white dust from the barrage. Around the Hezbollah compound in the southern district — known as Dahiyah — entire blocks were littered with heaps of rubble and twisted metal, and fires raged.

One building collapsed on its side like a sandwich, and other apartment buildings were reduced to rubble or had their upper floors collapsed into those below. The steel gates of the Hezbollah compound was mangled and buried in the rubble of the demolished structures inside.

Furniture pieces, blankets, mattresses, clothes and soft toys were scattered on the streets. A copy of the Quran, Islam's holy book, lay in the street with its dusty pagers fluttering until it was reverently lifted and kissed by a Hezbollah gunman.

Dahiyah was empty except for guerrillas and a few residents who returned to their homes to collect belongings before fleeing again to their refuges elsewhere.

"We want to sleep on our own pillows in the shelter," Mariam Shihabiyah, a 39-year-old mother of five said as she emerged from scrounging a few supplies from her apartment in a badly damaged building. "I just want them and our clothes, that's all ... Can you believe what happened to Dahiyah?"

Adam, the head of Israel's Northern Command, said Iranian troops were helping Hezbollah fire Iranian-made missiles at Israel. Hamid Reza Asefi, an Iranian Foreign Ministry spokesman, denied claims that his country had troops in Lebanon or had given missiles to Hezbollah.

Hezbollah guerrillas hit Haifa with a rocket for the first time ever Thursday. Israel responded by stepping up its airstrikes in Lebanon.

Olmert said that Israel's offensive did not intend to harm Lebanese civilians.

"We want to live our lives in peace and in good neighborly relations," he said. "Unfortunately, there are those who misinterpret our wishes for peace in the wrong way. We have to no intention of bending in the face of these threats."

"Our enemies are trying to disrupt the lifestyle in Israel. They will fail," he said.

The Associated Press contributed to this report.