The UN agency for Palestinian refugees said today it has halted all aid shipments into the Gaza Strip after the Hamas government seized thousands of tonnes of food and other provisions.

The UN Relief and Works agency said it made the decision after Hamas personnel intercepted an aid shipment for the second time this week.

In a statement, the agency said 10 truckloads of flour and rice delivered into Gaza yesterday were taken away by trucks affiliated with the Hamas-run social affairs ministry. Earlier this week, Hamas police took away thousands of blankets and food parcels meant for needy residents.

The UN said the suspension would remain in effect until the aid is returned and the agency receives credible assurances from the Hamas government that such thefts will end. There was no immediate reaction from Hamas.

UNRWA spokesman Chris Gunness said the agency would continue to distribute aid from its existing supplies in Gaza, but he warned that stocks were running thin.

"There is enough aid for days, not weeks," he said. Complicating the situation, he said that the agency has not been able to import plastic bags used for food distribution, and that existing supplies will run out early next week.

Some 80% of Gaza's 1.4 million people rely on the UN agency for food and other support, and UN officials say the need for aid has increased since Israel ended a military offensive in Gaza last month.

The offensive, meant to halt years of Hamas rocket attacks on southern Israel, killed nearly 1,300 people and caused widespread destruction.

Israel halted its Gaza operation on 18 January. Hamas then announced it would hold its fire.

However, sporadic fighting has persisted. Today, Gaza militants launched two more rockets into Israel, the military said. There were no injuries, but it illustrated the fragility of the Gaza truce.

The rocket attacks followed a border incident late yesterday in which Israeli forces shot and killed a Palestinian who the Israeli military claimed had neared the fence armed with a grenade.

Egypt's attempts to mediate a long-term ceasefire have failed so far. Hamas is demanding Israel open Gaza's blockaded border crossings as part of any agreement, but Israel says it will not turn the crossings over to Hamas control. It also wants international guarantees that weapons smuggling into Gaza will stop.