Hamas Chief Killed, Mideast Tense

Palestinians took to the streets in rage and Israel vowed to press its campaign against militants in the aftermath of its killing of the spiritual leader of Hamas on Monday.

Israel killed Ahmed Yassin in a helicopter missile strike outside a Gaza City mosque, unleashing threats of unprecedented revenge by Palestinian militants against Israel and the United States.

Palestinian areas were locked down after the killing and diplomats from the United States and elsewhere were meeting Monday in Cairo to assess its impact on the region.

National security adviser Condoleezza Rice told the CBS News Early Show, "everybody now needs to be calm."

Yassin, in his 60s, was the most prominent Palestinian leader killed by Israel in more than three years of fighting.

More than 200,000 Palestinians, some carrying billowing green Hamas flags, flooded the streets for the funeral procession, the largest gathering in Gaza City in recent memory.

At the cemetery, Yassin's body was carried to the grave between two rows of 200 militants each. The men were armed with anti-tank missiles and machine guns.

"Words cannot describe the emotion of anger and hate inside our hearts," said Hamas official Ismail Haniyeh, a close Yassin associate.

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

Israeli Prime Minister Ariel Sharon called Yassin the "mastermind of Palestinian terror" and a "mass-murderer who is among Israel's greatest enemies."

Sharon said Israel will press ahead with its war on terror, signaling there will be more targeted attacks and raids. "The war against terror has not ended and will continue day after day, everywhere," he said.

Fearing reprisal attacks, Israel sealed off the West Bank and Gaza and confined many West Bank Palestinians to their communities. The Rafah border crossing between Gaza and Egypt was also closed. Troops reinforcements were sent to Gaza, and security forces in Israel were placed on high alert.

In Lebanon, Hezbollah guerrillas shelled Israeli positions in a disputed border area on Monday for the first time in five months, triggering an Israeli airstrike and artillery fire, security officials said.

At daybreak Monday, Israeli helicopters fired three missiles as the wheelchair-bound Yassin, his bodyguards and dozens of others left a neighborhood mosque in Gaza City.

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

The Israeli attack was seen as a huge gamble by Sharon, who is trying to score a decisive victory against Hamas ahead of a possible Israeli withdrawal from Gaza.

The assassination was seen as a major escalation that drew condemnation from the Arab world and many European countries. British Foreign Secretary Jack Straw said the assassination "is unacceptable, it is unjustified and it is very unlikely to achieve its objectives."

In Cairo Monday, President Hosni Mubarak announced that in protest of the killing of Yassin, the planned visit of Egyptian legislators to Israel is being cancelled.

Asked about the killing's likely impact on the peace process, Mubarak replied: "What peace process?"

Envoys from the United Nations, United States, Russia and the European Union have arranged to meet for talks on the consequences of Israel's killing of the Palestinian militant leader Sheik Ahmed Yassin, Egyptian Foreign Minister Ahmed Maher said Monday.

Sharon's critics in Israel warned that the Yassin killing could be seen as an attack by Israel on Islam and unnecessarily widen the circle of conflict.

"My great fear is that this will be understood as an attack against a religious leader," said Interior Minister Avraham Poraz of the centrist Shinui Party.

Hamas promised a harsh response.

"Yassin is a man in a nation, and a nation in a man. And the retaliation of this nation will be of the size of this man," said Abdel Aziz Rantisi, a prominent Hamas leader.

For the first time, Hamas also threatened the United States, saying America's backing of Israel made the assassination possible. Rival militant groups also promised revenge.

The Palestinian Authority said in a statement that "Israel has exceeded all red lines with this cheap and dirty crime," and declared a three-day mourning period. Palestinian schools were closed.

Flags at Yasser Arafat's headquarters in the West Bank town of Ramallah were lowered to half-staff, and the Palestinian Cabinet held an emergency session. Yassin was Arafat's biggest political rival, but Arafat was always careful not to confront the Hamas leader openly.

Ministers stood around an oval-shaped table in the Cabinet room as Arafat recited a Muslim prayer for Yassin. Arafat then added: "May you join the martyrs and the prophets. To heaven, you martyr."

Earlier Monday, about 2,000 demonstrators gathered outside Arafat's headquarters, screaming for revenge and demanding to speak to the Palestinian leader. Arafat remained inside, apparently fearing he, too, might be targeted by Israel.

However, an Israeli security official said there were no immediate plans to target Arafat, and that Hamas was the focus of Israel's current offensive.

Rice told the Early Show that the United States did not approve of the attack ahead of time.

"But let's remember that Hamas is a terrorist organization and that Sheik Yassin himself has been heavily involved in terrorism," Rice said.

She added that the U.S. "would just ask everybody to step back and be calm and try very hard not to do something that might preclude a better day."

Since September 2000, 474 people - the majority of them Israelis - have been killed in 112 Palestinian suicide bombings, most of them carried out by Hamas.

More than 150 Palestinian militants have been killed in targeted raids, according to Palestinian medical officials, though that total also includes militants killed resisting arrest.

Some 2,000 Palestinians and 900 Israelis have been killed overall.

Israel tried to kill Yassin in September but failed. One Israeli official recently said Yassin, a Hamas founder, was "marked for death."