At least four Palestinians have been killed in an Israeli ground incursion into the Gaza Strip. As Robert Berger reports from VOA's Jerusalem bureau, the violence is casting a shadow over efforts to revive the peace process.

Israeli tanks pounded Palestinian militant positions as they rolled across the border into southern Gaza Tuesday. The incursion sparked clashes with militants armed with assault rifles, rocket propelled grenades and landmines.

Israeli aircraft also fired on militants in northern Gaza.

The army said the raids are aimed at halting Palestinian rocket attacks that have terrorized Israeli border communities.

"Israel's position is clear," said Israeli spokesman Mark Regev. "The current situation is intolerable and we will act to defend our people."

It was the biggest Israeli ground incursion since the Islamic militant group Hamas seized control of Gaza in June, routing the Fatah forces of western-backed Palestinian President Mahmoud Abbas.

The fighting came a day before Israel and Mr. Abbas's Palestinian Authority in the West Bank are to resume formal peace talks after a seven-year break. The negotiations were agreed upon at the Annapolis peace conference in the United States two weeks ago.

The radical Islamic Jihad group, which suffered casualties in the Gaza fighting, said the Israeli ground assault is the fruit of Annapolis.

Islamic Jihad spokesman Daoud Shihab said Israeli aggression is proof that Annapolis was a failure. Both Islamic Jihad and Hamas refuse to renounce violence and oppose peace talks with Israel.

Palestinian officials in the West Bank also condemned the Israeli incursion. They accuse Israel of sabotaging peace talks even before they begin.