The humanitarian crisis in Gaza deepened yesterday when the main United Nations aid agency suspended its work in the Strip after one of its drivers was killed by an Israeli tank shell.

The International Committee of the Red Cross (ICRC) also said it would restrict its operations after one of its lorry drivers was hurt when a convoy carrying drugs for Gaza hospitals and transferring intensive care patients to Egypt came under fire from Israeli troops south of Gaza City. Both organisations said their convoys had been co-ordinated with the Israeli military.

"If [the Israeli military] give us clearances to move, then it is fully unacceptable that their soldiers on the ground are going to fire on our workers. Believe me, the verbal assurances [from the Israelis] have run out in terms of credibility."

The UN decision to halt aid came on the 13th day of Israel's offensive. A second three-hour ceasefire allowed rescue workers and doctors into some of the most heavily-targeted zones and to retrieve about 50 bodies, bringing the Palestinian death toll to 758. The UN, which claims civilians have borne the brunt of the bloodshed, said 257 of the dead were children under 18.

The UN driver was the third to be killed during Israel's offensive. The UNRWA said a second convoy seeking to recover the body of another UN casualty during yesterday's ceasefire was also fired at but no one was hurt.