GAZA CITY, Gaza Strip ? Israeli helicopters and tanks hit Gaza City early today, targeting a main Palestinian security compound.

Despite all the violence and a sudden, bitter Israeli election campaign, negotiations continue over a U.S.-European plan to put an end to the Mideast conflict, according to a document obtained by The Associated Press.

In Gaza City, Israeli helicopters fired missiles at the headquarters of Preventive Security, the main official Palestinian force, knocking down a wall, security officials and witnesses said.

As tanks moved into the city, Israeli gunboats opened fire on the shoreline, shelling the area where Palestinian leader Yasser Arafat’s office was. The complex was destroyed in an Israeli attack several months ago.

Initial reports said two Palestinian security officers were lightly wounded as they ran away from the base. However, the Palestinian security chief, Maj. Gen. Abdel Razek Majaidie, said that Israeli forces blocked roads, preventing ambulances from entering, and cut phone lines. Officials at nearby Al-Quds hospital said Israeli forces fired at one of their buildings.

A TV cameraman working for the Reuters news agency was lightly injured by tank fire, doctors said.

The Israeli military said that attack helicopters struck Gaza and tanks were involved in the operation.

The sounds of explosions could be heard all over the city of about 300,000 Palestinians. Witnesses said troops fired shells at the house of Yusuf Mukdad, a Preventive Security officer arrested recently by the Israelis on suspicion of planning attacks against Israelis.

Mustafa Mughrabi, 45, lives near the Preventive Security base and told The Associated Press by telephone that he was hiding under a bed with his children after gunfire hit his house from three directions. Outside, he said he heard “the sound of explosions mixed with screams of children.”

Palestinian official Tayeb Abdel Rahim lives about 100 yards from the targeted base. He told the AP that his house was hit by bullets, but he was not harmed. He called the Israeli operation “aggression” and warned that “security and stability for Israeli people cannot be achieved at the expense of the Palestinian people.”

So far Gaza has been spared the large-scale military operations in which Israel has taken control of most West Bank Palestinian population centers, retaliation for bloody terror attacks. However, Israeli leaders have said that militant groups operate unfettered in Gaza, and the Israeli military would confront them at some point.

On Sunday, Israelis buried most of the 12 soldiers and security guards killed in a Palestinian ambush in Hebron on Friday night, as Israeli troops and tanks fanned out through the West Bank city.

The soldiers were guarding Jewish worshippers returning on foot from Hebron to the nearby settlement of Kiryat Arba.