The raids killed three militants in the south and one in the north and came a day before Israeli and Palestinian negotiating teams were due to sit down for the first time since peace talks were formally resumed at a U.S. conference.

In southern Gaza, three members of the radical Islamic Jihad group were killed by an Israeli tank shell as around 30 tanks pushed around two kilometers (more than a mile) into the territory.

The victims were Mohammed Abu Hamra, Ibrahim Baroud, and Jihad al-Aswad, all of them in their 20s, the group said.

Shortly afterward, seven other militants were wounded in an Israeli air raid in the same area, they added.

Earlier an army spokeswoman said that the military had carried out two air raids in the area against militants who had approached Israeli troops. She said the Israelis identified hitting some of them, but did not provide details.

The troops cut traffic on the main road dissecting Gaza from north to south and encountered fierce resistance from Palestinian fighters on the ground, the medics and witnesses said. Two Israeli soldiers were lightly wounded when a rocket-propelled grenade hit their tank, an army spokeswoman said.

Dozens of suspected militants were detained by Israeli soldiers as they conducted house-to-house searches in the area, witnesses said.

The incursion was Israel's largest in months in Gaza in terms of the number of Israeli troops and material involved and the distance penetrated into the impoverished territory, Palestinian sources said.

The army spokeswoman described the operation as "pretty routine during the latest period, with all the mortar shelling and rocket launching coming from the area ... it's not something out of the ordinary."

Early Tuesday, an Islamic Jihad fighter was killed in an Israeli air raid near Gaza's northern town of Beit Hanun, medics said.

Israel has conducted regular air raids and limited ground incursions in Gaza since mid-June, when the Islamist Hamas seized power in the territory after routing forces loyal to President Mahmoud Abbas.

The operations have failed to completely curb fire from militants, with mortar shells or rockets fired from the territory into Israel on a daily basis, mostly without causing casualties.

Hamas, which does not recognize Israel's right to exist, fiercely opposes negotiations which Abbas formally revived along with Prime Minister Ehud Olmert at a peace conference in the U.S. city of Annapolis in late November.

The steering committee that is to oversee the renewed negotiations will meet for the first time Wednesday in Jerusalem, amid uproar over Israel's plans to expand a settlement in the east of the holy city.

A spokesman for the dismissed Hamas government slammed Tuesday's operation and urged the Palestinian Authority to call off Wednesday's peace talks.

"Faced with this atrocious crime the government calls the Palestinian negotiators not to go to tomorrow's meetings with the aggressors and to cut all contact with them," said Taher al-Nunu. "It will be shameful to shake hands stained with blood."

Abbas' spokesman Nabil Abu Rudeina slammed the raids as an "abominable crime" and said they "reinforce doubts about Israel's desire to assure the success of the negotiations that start tomorrow."

© 2007 Agence France-Presse