Gaza City - Several Israeli tanks and bulldozers crossed into the south-east Gaza Strip Tuesday morning, sparking clashes with Palestinian gunmen, witnesses and the Israeli military said.

The witnesses said that three tanks and two bulldozers rolled some 100 metres across the border east of the town of Rafah. They said the bulldozers were clearing cultivated land.

An Israeli military spokeswoman said a small force was on a "routine activity" to uncover explosive devices, which are frequently planted by militants along the border fence.

She said local gunmen fired two mortar shells at the force.

The armed wing of the radical Islamic Hamas movement, the al- Qassam Brigades, said in a media statement that its fighters were engaging the Israeli troops.

The clash comes amid a crumbling Israeli-Palestinian truce in Gaza, which took effect June 19 and had largely held for the past five months. It was shaken when Israeli troops crossed just over the border into Gaza on November 4 to destroy a tunnel dug by militants. Israel said the militants were plotting to abduct soldiers from Israeli territory.

That incursion had sparked heavy clashes with local militants and left six Palestinians dead, most of them members of Hamas' armed wing. Since then, Gaza fighters have resumed their rocket attacks on Israel.

The Popular Front for the Liberation of Palestine (PFLP), along with an offshoot of Palestinian President Mahmoud Abbas' Fatah movement, meanwhile claimed responsibility for firing another five rockets and three mortar shells from the Gaza Strip into Israel overnight.

Responding to the rocket-fire, Israel extended its near-total closure of the Gaza Strip for the 14th consecutive day.

The United Nations agency for Palestinian refugees (UNWRA) managed to resume its food distribution to residents of Gaza refugee camps after Israel allowed 33 trucks with basic food items and medical supplies into Gaza Monday.

No fuel however has been allowed into Gaza since Thursday. The strip's only power station, which runs on industrial diesel and provides some 30 per cent of Gaza's electricity needs, has shut down. (dpa)