GAZA CITY, Gaza Strip ? Holding up the flag-wrapped body of a 2-month-old girl, tens of thousands of Palestinians marched Tuesday to bury their dead after an Israeli airstrike killed a top Hamas leader and 14 civilians, including nine children. The Islamic militant group vowed revenge.

President Bush called the Israeli missile strike “heavy-handed,” joining other world leaders in sharp criticism of the attack, which leveled an apartment building and destroyed other nearby buildings in a crowded neighborhood of Gaza City overnight.

The Israeli prime minister hailed the operation, which successfully targeted Salah Shehadeh, the top commander of Hamas’ military wing, Izzadine el-Qassam.

“This operation was in my view one of our biggest successes,” Ariel Sharon told Cabinet ministers. “We hit perhaps the most senior Hamas figure on the operational side,” Sharon said of Shehadeh, who was jailed first by Israel, and then by the Palestinians, from 1988 to 1999.

However, some Israelis criticized the attack, warning that the killing of a top Hamas commander would trigger a surge of suicide bombings in retaliation.

“The death of innocent children will only encourage more desire for revenge and motivation for more terror attacks,” said member of parliament Ran Cohen, a reserve colonel in the Israeli military.

Israel linked Shehadeh to Hamas’ deadliest suicide bombings, including a March attack at a Netanya hotel that killed 29, a June 2001 disco bombing in Tel Aviv that killed 21, and an August 2001 bombing at a Jerusalem pizzeria that killed 15.

In Gaza, tens of thousands crowded the streets in an emotional and angry funeral procession for Shehadeh and the other victims of the airstrike.

As wailing relatives held aloft the youngest victim wrapped in a Palestinian flag, the infant’s face and black hair visible between the folds, gunmen fired rifles in the air and called for revenge.

“Do you want peace with the Jews?” asked an activist with a loudspeaker. “No!” the crowd responded.

Arafat called the attack a “disgusting, ugly crime, … a massacre no human being can imagine.” Saudi Foreign Minister Prince Saud al-Faisal called the strike a “horrible act” with “no ethical, moral or even military justification.”

In a rare U.S. criticism of Israel, White House spokesman Ari Fleischer said “this heavy-handed action does not contribute to peace.”

The office of U.N. Secretary-General Kofi Annan said “Israel has the legal and moral responsibility to take all measures to avoid the loss of innocent life.”

Swedish Foreign Minister Anna Lindh called it “a crime against international law and morally unworthy of a democracy like Israel.”