A huge explosion rocked the center of Baghdad just before daybreak Saturday, as allied ground troops continued their march toward the Iraqi capital.

U.S. officials have told Fox News late Friday that the government is confident that Saddam Hussein was seen being rushed into an ambulance on a stretcher after the missile strikes on March 19 -- the first strike of the Iraq war. The government is in possession of images that show what is described as "panicked digging" immediately after the initial strikes on Wednesday night, with bodies seen being removed from the impact zone.

Officials also told Fox News that some top security and military personnel have been fleeing Baghdad, and more are preparing to leave.

"The erosion from Baghdad has begun," one official says.

Aircraft could be heard buzzing overhead in Baghdad on Saturday, but the target of the apparent assault was unknown. Sirens presumably from ambulances or police cars blared throughout the city after the blast. The Associated Press reported a single blast; Reuters reported two.

The blast at first light interrupted the silence that had fallen over the city after the barrage of missiles Friday evening that marked the beginning of the "Shock and Awe" phase of Operation Iraqi Freedom.

Reuters also reported that shortly thereafter a large explosion was heard outside the city, setting off air raid sirens.

Two British Royal Navy Helicopters collided over the Persian Gulf on Friday morning, killing all seven crew members.

Meanwhile, coalition troops secured major resources and captured strategic towns, assuring the Iraqi people that they will soon be liberated from Saddam Hussein. The allied ground troops had reportedly made it as far as one-third of the way to Baghdad from the Iraqi border.

Senior Defense officials told Fox News that Special Forces units and a new team called the 75th Exploitation Task Force are now hunting for weapons of mass destruction in Iraq.

The 75th Exploitation Task Force has Army chemical and biological weapons teams, as well as Department of Defense civilian scientists.

The teams had a list of about 100 targets at the beginning of their mission, but that list has reportedly expanded.

In southern Iraq, an entire division of the Iraqi army, numbering 8,000 soldiers, surrendered to coalition forces, Pentagon officials said.

Iraq's 51st Infantry Division surrendered as the allies advanced toward Basra, Iraq's second largest city. The mechanized division had about 200 tanks before the war, according to independent analysts and U.S. officials.

The 51st was one of the better equipped and trained in Iraq's regular army forces and was the key division protecting Basra, a major transportation and oil shipment hub on the Shatt al-Arab waterway that leads to the Persian Gulf.

 

Meanwhile, Baghdad took a terrific pounding from allied missiles, which rained bombs throughout the city. Huge fireballs rocked the heart of the capital, and the sky filled with smoke. Air raid sirens blared in the city throughout the night.

"Baghdad is burning," said a correspondent for the Al-Jazeera television network. "What more can we say."

The spectacular blasts lit up the night sky, illuminating the city even as they decimated it. At one point, the sound of a missile roared through the street before exploding into a fireball.

The Iraqis responded by opening up anti-aircraft bursts.

Saddam's presidential palace was ablaze after being hit by two rounds of missiles, beginning around 7 p.m. (11 a.m. EST).

Three major fires raged on the Old Palace compound on the west side of the Tigris River. The palace compound is the heart of the Iraqi state and includes the offices of the prime minister's staff and the Cabinet.

The turquoise-domed main building appeared to be untouched. But a building next to the palace was on fire, and black smoke billowed from another 10-story building in the compound.

The city's nine-story intelligence headquarters appeared to have been damaged by allied fire.

In an address Saturday, Information Minister Mohammed Saeed al-Sahhaf reassured Iraqis that the fighting was "fierce," and claimed Iraqi forces had destroyed five tanks.

He said most of those captured by allied forces were civilians, not soldiers, and claimed to have destroyed five tanks. He added that more than 200 Iraqis had been injured, including women, children and other civilians who were being treated at five hospitals.

Earlier, when asked whether Iraq plans a counterattack, al-Sahhaf said, "Our leadership and our armed forces will decide this, in what guarantees the defeat of those mercenaries, God willing."

"This criminal (Bush) in the White House is a stupid criminal," he added.

In the first stages of the air campaign, 1,000 to 1,500 bombs and Tomahawk Cruise missiles were to be used against a variety of targets throughout Iraq.

A senior Pentagon official said air operations will continue on a 24-hour basis all over the country.

The official said that the Baghdad targets hit within the first 90 minutes of airstrikes included: command, control and communications facilities, including state-run radio and television; buildings and facilities key to Saddam's regime; Iraqi intelligence service facilities; Special Security Organization (SSO) facilities; and Republican Guard installations.

A huge fire was raging in the south, where a major oil refinery and military installations are located. Air strikes were also occurring in Mosul, and bomb flashes were seen in the northern city of Kirkuk.

Fox News has learned that at least 40 U.S. cruise missiles pounded two villages in Northern Iraq early Saturday, targeting locations where Al Qaeda operative Abu Musab Zarqawi spent time during his stay in Iraq. Zarqawi, an associate of Usama Bin Laden, stayed at terrorist training camps in that region, and is the person who Secretary Powell and President Bush both referenced when they make the connection between Al Qaeda and Iraq.

Gen. Richard Myers, chairman of the Joint Chiefs of Staff, said earlier in the day that several hundred targets would be hit on Friday.

At the southern tip of Iraq, Fox News correspondent Steve Centanni reported that Navy SEAL teams have come on shore. The Marines are now in control of the area secured by the SEALs, which means the United States now controls two main oil shipment terminals.

Some allied leaders believe the Iraqis intended to rig the terminals with explosives and detonate them in a defensive move.

"The regime is starting to lose control of their country," Secretary of Defense Donald Rumsfeld said during a news briefing at the Pentagon. "Our goal is to defend the American people and to eliminate Iraq's weapons of mass destruction and to liberate the Iraqi people."

A senior U.S. government official told Fox News that Iraqi command and control communications are "sporadic and jumbled."

"We do not know who is in charge," the official said. "We think they don't know who is in charge. They're confused, disoriented and disorganized, and it's only going to get worse for them."

As many as 3,000 precision-guided bombs will be dropped on specific targets in Iraq during this phase of the campaign, officials said.

"We will continue to do whatever we can to change this Iraqi regime. We will use everything in our arsenal to do that," a senior Defense official told Fox News.

Included in that arsenal is the Massive Ordnance Air Blast bomb. The 21,000-pound MOAB has been nicknamed the Mother of All Bombs.

Dozens of F-14 Tomcats and F/A-18 Hornet strike planes loaded with bombs roared off the deck of the aircraft carrier USS Kitty Hawk before nightfall Friday.

Coalition forces are giving the Iraqi military one last chance to lay down their arms.

"We're getting surrenders faster than we can handle them," a U.S. official told Fox News.

The war's top commander -- Gen. Tommy Franks -- planned to "scale" the intensity of the bombardment, depending on how the surrender talks are going.

The first attack on Baghdad came from 320 Tomahawk cruise missiles fired by ships in the Persian Gulf and the Red Sea, said Rear Adm. Matthew G. Moffit, commander of the Kitty Hawk battle group. They were fired about 20 minutes before the first explosions occurred.

Iraqi defense minister Lt. Gen. Sultan Hashim Ahmed said Friday that coalition forces were targeting the southern cities of Basra and Nasiriyah.

B-52s Take Off

Earlier in the day, eight American B-52 bombers took off from Fairford Airbase in Britain. One U.S. official said the B-52s had been scrambled en masse and the air strikes would be bigger than anything seen thus far.

On Wednesday, six other B-52s left Fairford to be pre-positioned closer to Iraq.

Each of the 14 B-52s can carry 12 Joint Direct Attack Munitions (JDAMs), eight Conventional Air Launched Cruise Missiles (CALCMs) inside and another 12 externally, or a variety of other non-precision bombs.

Elsewhere, Marines on Friday secured the Iraqi border town of Umm Qasr, giving coalition forces access to a port for military and humanitarian supplies and hastening the end of Iraqi resistance in the south. A couple of hundred prisoners were taken.

U.S. Navy vessels in the Persian Gulf seized at least one Iraqi missile ship and two tug boats that had at least 50 land mines aboard.

American forces also seized two key western Iraqi airbases, which will now be used by coalition forces. The bases were near the so-called "Scud Box," where it was feared Iraq could launch Scud attacks on Israel.

Meanwhile, two U.S. Marines were killed in combat on Friday, marking the first combat casualties of the war. Four other Marines and eight Britons also were killed in a helicopter crash in Kuwait.

The two Marines who died in combat were with the 1st Marine Expeditionary Force. One died early Friday while his platoon battled Iraqi infantry to secure an oil pumping station in southern Iraq. The second died in the afternoon while fighting Iraqi forces near Umm Qasr.

Coalition troops took the border town of Safwan, tore down signs of Saddam and told nervous residents: "Saddam is done." A woman threw herself at the Marines' feet until a man hurriedly came and led her away.

Also in Safwan, some local residents joined Maj. David Gurfein in a cheer. "Iraqi! Iraqis! Iraqis," he yelled, pumping his fist in the air.

"We're very happy," said one Iraqi man. "Saddam Hussein is no good. Saddam Hussein is a butcher."

Iraq also fired another Scud missile toward Kuwait on Friday, but Patriot missiles successfully intercepted the rocket over the desert.

Military officials hope to take Basra Friday night. Forces could enter Baghdad within the next three or four days.

Britain is preparing to take humanitarian aid into Iraq within 48 hours.

Fox News' Major Garrett, Chris Wright, Ian McCaleb, Bret Baier, Rita Cosby, Carl Cameron and The Associated Press contributed to this report.