Troops in jeeps and armoured vehicles accompanied by bulldozers and with a helicopter gunship as air support entered the Palestinian territory east of Rafah, which straddles Gaza's border with Egypt, they said.

Three Palestinians were detained, and several houses were damaged in the incursion, the sources said.

They also said that a poultry farm was completely destroyed, and estimated losses at a million dollars.

Witnesses in the north of the impoverished and densely populated coastal strip said there was a second raid near Jabaliya refugee camp, but no casualties or damage were reported.

An Israeli military spokesman in Tel Aviv told AFP he was unaware of any operations in Gaza.

© 2008 Agence France-Presse