Israeli tanks and bulldozers entered a Palestinian area of the Gaza Strip (search) late Thursday, residents said, after soldiers shot and killed three Palestinians who were apparently trying to infiltrate a Jewish settlement.

It was the most serious incident since Israel's assassination of the founder of Hamas (search), Sheik Ahmed Yassin (search), in a Monday air strike in Gaza City.

The military said an armed cell of three Palestinians opened fire on an army outpost and a civilian vehicle at the settlement of Tel Katifa, opposite the Palestinian town of Deir e-Balah in central Gaza near the Mediterranean seacoast.

In a heavy exchange of fire, the three Palestinians were killed. The military said there were no Israeli casualties.