Israeli Tanks Enter Gaza After Hamas Head Killed

Israeli tanks rolled into the Gaza Strip late Monday to stave off Palestinian rocket fire against Jewish communities, following the Israeli assassination of Hamas founder Sheik Ahmed Yassin (search).

Israeli security officials said the tanks closed in on the northern Gaza town of Beit Hanoun to prevent Palestinians from firing more homemade rockets and mortar shells.

Monday's attacks, aimed at Israeli towns and Jewish settlements in and near Gaza (search), were the first action taken following Palestinians' promised retaliation for Yassin's death.

No one was killed and no damage done as a result of the Palestinian rocket strikes, and there weren't any exchanges of fire reported.

The Yassin assassination was part of Prime Minister Ariel Sharon's effort to crush Hamas ahead of a possible Israeli withdrawal from Gaza.

But the killing was seen as a major gamble that could galvanize the Palestinians behind Hamas. Rival Palestinian militant groups immediately pledged solidarity with Hamas.

To the north, Hezbollah guerrillas launched an anti-tank missile at Israeli troops along Israel's border with Lebanon, and Israel responded with an airstrike and artillery fire. No casualties were reported.

U.S. Threatened in Promises of Revenge

Earlier Monday, hundreds of thousands of Palestinians chanting "revenge, revenge" flooded Gaza's streets Monday to bury Yassin, as militants pledged unprecedented retaliation — including first-time threats of violence against the United States.

Homeland Security Secretary Tom Ridge said he was heeding the Hamas terror warning.

"If they are threatening the United States, we have to take it quite seriously," he told reporters in Washington.

While not condemning the assassination, the State Department said it increased tensions and would make it harder to pursue peace in the Middle East. "We are troubled," spokesman Richard Boucher said.

U.N. Secretary-General Kofi Annan and many world leaders condemned Monday's killing of Yassin, the most prominent Palestinian targeted by Israel in 3 1/2 years of fighting. The Bush administration said it was "deeply troubled" by the attack.

"The United States did not have any advance warning and did not approve of the strike," national security adviser Condoleezza Rice told Fox News on Monday.

But Hamas supporters vowed to strike back and for the first time threatened the United States.

"We will get revenge for every drop of blood that spilled," said Salman Bdeiri, a Hamas supporter crying near the mosque where Yassin prayed shortly before being killed by an Israeli airstrike.

Israel sealed off the West Bank and Gaza, banning Palestinians from Israel, and placed its security forces on high alert.

The missile strike dealt what could be the final blow to the stalled U.S.-led "road map" peace plan. It also angered Egypt and Jordan, moderate Arab states whose tacit support Sharon needs for any unilateral withdrawal from Gaza.

The attack came before daybreak, when Israeli helicopters swooped toward a Gaza street and fired three missiles as Yassin — a quadriplegic who used a wheelchair — left a mosque with his bodyguards and dozens of others.

Since Yassin founded Hamas in 1987, the group has killed hundreds of Israelis in scores of attacks. Hamas wants to destroy the Jewish state and replace it with an Islamic one.

For the first time Monday, Hamas threatened the United States and suggested it might seek outside help in carrying out revenge attacks.

"The Zionists didn't carry out their operation without getting the consent of the terrorist American administration and it [the United States] must take responsibility for this crime," Hamas said in a statement. "All the Muslims of the world will be honored to join in on the retaliation for this crime."

In the past, Hamas has refrained from targeting U.S. citizens or interests, instead focusing on fund-raising and recruitment within the United States, according to senior U.S. law enforcement officials.

Batsheva Genut, spokeswoman for Israel's foreign ministry, told Fox News that the absence of a Palestinian Authority effort to fulfill the Mideast peace road map is to blame.

"Israel doesn't relish the role it's being forced to play today," she said.

Israel Vows to Fight On in War Against Terror

But Israel said it will press ahead with more targeted attacks and raids.

"The war against terror has not ended and will continue day after day, everywhere," Sharon said. He called Yassin the "mastermind of Palestinian terror" and a "mass murderer who is among Israel's greatest enemies."

More than 200,000 Palestinians, some carrying billowing green Hamas flags, poured into the streets of Gaza City for Yassin's funeral procession, the largest gathering here in recent memory. Tens of thousands of furious Palestinians rallied across the West Bank.

Mourners in Gaza jostled to touch Yassin's flag-draped coffin, and women ululated and threw flowers and candy. Two Israeli helicopters flew above, and the sky was blackened from the smoke of burning tires.

At the cemetery, Yassin's body was paraded through an honor guard of 400 militants armed with anti-tank missiles and machine guns.

"Our leader has left us, but we say to him, 'Your lessons will stay within our hearts and minds and our generations,'" Abdel Aziz Rantisi, a Hamas leader, said in a eulogy.

In addition to Yassin, who was in his 60s, 12 Palestinians were killed Monday, seven in the airstrike, four in clashes with Israeli troops and one while handling explosives.

During the strike on Yassin and his entourage, blood and flesh splattered on the walls of the mosque. Nearby windows shattered. Only a charred metal seat and two twisted wheels were left of Yassin's wheelchair, and a blood-soaked brown shoe lay in the street. Lying in tatters nearby was the brown blanket in which Yassin was nearly always wrapped.

"Two or three people were lying next to him on the ground. One was legless," said taxi driver Yousef Haddad.

Among those killed were several of Yassin's bodyguards and his son-in-law. Seventeen people were wounded, including two of Yassin's sons.

After the attack, residents rubbed their hands in pieces of gravel mixed with Yassin's blood, a traditional sign of anger and a preparation for revenge.

Arafat Rattled

The Palestinian Authority declared three days of mourning and closed schools. Flags at Yasser Arafat's headquarters in the West Bank town of Ramallah headquarters were lowered to half-staff.

Palestinian ministers stood as Arafat recited a Muslim prayer for Yassin and then added: "May you join the martyrs and the prophets. To heaven, you martyr."

The missile strike shook Arafat in more ways than one. The massive outpouring of support for Hamas showed how formidable a rival the Islamic group has become to Arafat's weakened Palestinian Authority.

Arafat also fears he may be next on Israel's hit list, said a confidant, Communications Minister Azzam Ahmed.

However, an Israeli security official, speaking on condition of anonymity, said Israel's campaign focuses on Hamas, at least for now.

Boucher, the State Department spokesman, urged Israel to keep its promise to not harm Arafat. "We think that's an important pledge and we would expect them to stand by that."

Israeli Defense Minister Shaul Mofaz said Yassin's killing will eventually weaken Hamas.

"If we have to balance how many more terrorists Yassin would have sent, how many terror attacks he would have approved, if we weigh this on the scales, we acted rightly," Mofaz was quoted as telling a parliamentary committee.

But Sharon's critics in Israel warned that the Yassin killing could be viewed as an attack on Islam.

"This had nothing to do with security, nothing to do with protecting Israeli citizens. It's all about politics and public opinion," said lawmaker Yossi Sarid of the dovish Yahad Party.

Yassin's killing virtually buried hopes of reviving the road map, which envisioned an end to violence and the creation of a Palestinian state by next year.

"Such actions are not only contrary to international law, but they do not do anything to help the search for a peaceful solution," Annan said of the assassination.

European and Arab leaders condemned the killing. Egypt canceled a trip by legislators and other dignitaries to Israel to mark the 25th anniversary of the peace treaty between the two countries.

British Foreign Secretary Jack Straw said the assassination "is unacceptable, it is unjustified and it is very unlikely to achieve its objectives."

Joseph Paritzky, Israel's minister of energy, said Yassin's assassination may bring more attacks on Israel.

"We are expecting a big retaliation from a terrorist movement and I do care about the lives of my citizens," Paritzky told Fox News. "I think it raises the morale of the people of Israel … but I think that we will not gain enough benefits from his killing."

The Israeli defense minister said Yassin was the "Palestinian bin Laden." Gideon Meir, an Israeli Foreign Ministry official, said Yassin was directly responsible for the scores of homicide attacks Hamas unleashed since 2000.

"He's not a spiritual leader — Mother Theresa was a spiritual leader. This is a thug who killed hundreds of people," Ambassador Alon Pinkas, New York Israeli consul general, told Fox News. "We've done, morally, the right thing."

Fox News' Wendell Goler, Jennifer Griffin, Liza Porteus, Teri Schultz, Catherine Donaldson-Evans and the Associated Press contributed to this report.