Khan Younis, Gaza Strip ? The Islamic militant group Hamas threatened new attacks Monday after Israel fired a missile into a crowded Gaza street and killed 11 Palestinians. The United States said it was “deeply troubled” by the raid in which three other Palestinians died and 110 were wounded.

Israeli said its troops were searching for Hamas militants when they raided Khan Younis with 40 tanks backed by helicopters shortly after midnight Sunday. Most of the dead fell victim to a missile fired into a crowd. The Palestinians said they were civilians. Israel said most were fighters killed in battle.

“Everyone should know that as our people were not safe in Khan Younis, so Israelis will not be safe in Tel Aviv,” said Abdel Aziz Rantisi, a Hamas leader. “We will strike everywhere.”

In Washington, State Department spokesman Richard Boucher couched U.S. criticism of the operation with a restatement of American support for Israel’s right to self-defense.

“We’re deeply troubled by the reports of Israeli actions in Gaza over the weekend,” he said, while adding: “We’ve always respected Israel’s right to defend itself, including going after armed groups and armed men in some of these areas.”

Javier Solana, the European Union’s visiting foreign policy chief, said he was shocked by the number of casualties. “I think that it is even more dramatic because of the efforts that the Palestinian people were making in order to get out of the way of violence in recent weeks,” he said.

Israel’s deputy defense minister, Weizman Shiri, regretted the loss of civilian life. “But what can we do?” he said. “It’s war.”

The four-hour raid was the deadliest against the Palestinians in three months. Twenty-five of the injured were in critical condition, doctors said; most suffered shrapnel wounds in the head, chest and abdomen. The dead ranged in age from 14 to 52.

The Israeli military said Khan Younis is a stronghold of the Islamic militant group Hamas, which has killed hundreds of Israeli civilians in suicide bombings.

It said during the raid, troops arrested a wanted man carrying a homemade explosive device. But there was no indication of a specific target, as in previous strikes against wanted militants that also claimed civilian casualties.

Palestinians burn tires as they gather around the area where an Israeli missile fired from a helicopter killed residents in Khan Younis, Gaza Strip. Fourteen Palestinians were killed and 110 wounded early Monday during an Israeli incursion into the southern Gaza city.

As the raid began, the military said soldiers exchanged fire with armed Palestinians, killing two. Doctors said a 45-year-old woman also died. The missile was fired in a densely populated neighborhood as the Israelis were pulling out.

Brig. Gen. Yisrael Ziv, the army commander in the area, said troops met heavy resistance from Palestinian gunmen gathered in the streets as the Israelis withdrew.

“They fired a lot and threw grenades. There was a battle there,” he said. “The helicopter aimed at this armed group and hit them.”

Palestinian witnesses gave a different account.

Wissam Abdeen, who was hit by shrapnel in the arm, said as troops withdrew, residents emerged from homes to inspect the damage, and there were no gunmen in the crowd. Another witness, Walid Sabah, whose 17-year-old son Abdullah was killed by the missile, said there were armed men in the street but they were not shooting.

Abdeen said as troops withdrew, he heard helicopters. “A big explosion lifted me and blew me 30 feet away,” he said.

Ziv said the battle was filmed from a pilotless plane; the army has not responded to an Associated Press request to see the footage. Ziv said none of the dead Palestinians was on Israel’s wanted list.