Jerusalem ? A bomb went off under a tank in the Gaza Strip Thursday, killing three Israelis and wounding two, military officials said, as European diplomats stepped up an offensive to end Israeli-Palestinian violence.

The attack followed an Israeli incursion into Gaza that was denounced by the Palestinian leadership as a “dangerous escalation” in violence. It was Israel’s largest operation in Gaza during 16 months of Israeli-Palestinian clashes.

The military officials, speaking on condition of anonymity, said Palestinians opened fire on a civilian convoy guarded by soldiers and set off a bomb. The Israelis responded by sending a tank into the area and soon after a second, larger bomb exploded under it, they said. Israel Radio and TV said the casualties were soldiers in the tank.

The bombing took place near the Netzarim intersection southeast of Gaza City, the officials said.

About 5,000 Israeli settlers live in Gaza among more than a million Palestinians. Israel controls the main roads through Gaza, and soldiers protect convoys of civilian vehicles entering and leaving the settlements.

Israeli forces pulled out of the last of three Gaza towns Wednesday, ending an 18-hour operation launched in response to rocket fire Sunday by Palestinian militants. Five Palestinians were killed during the raids.

Palestinian leadership denounced the incursion. Israeli commentators questioned its effectiveness, saying the main suspects from the Hamas militant group has escaped. All but two of 18 Palestinians arrested during the sweeps were released, military sources said.

Meanwhile, German Foreign Minister Joschka Fischer said the United States must work with other nations to achieve peace in the Middle East.