The United Nations aid agency has suspended its operations in the Gaza Strip in the wake of a series of Israeli attacks on its personnel and buildings.
"UNRWA decided to suspend all its operations in the Gaza Strip because of the increasing hostile actions against its premises and personnel," Adnan Abu Hasna, a Gaza-based spokesman for the United Nations Relief and Works Agency, UNRWA, said on Thursday.
The move came after Israeli tanks shelled a UN convoy earlier in the day, killing a Palestinian UN worker and injuring two others, as lorries were travelling to the Erez crossing to pick up humanitarian supplies meant to have been allowed in during a three-hour suspension of fire.
At least three UN-run schools have also been hit by Israeli fire, killing scores of civilians, during the 13 days of Israel’s assault on the Gaza Strip.
John Ging, the head of the UN relief agency in Gaza, said that the casualties in the convoy attack were Palestinian civilian contractors hired to bring supplies from the crossing points.
"They were co-ordinating their movements with the Israelis, as they always do, only to find themselves being fired at from the ground troops," he told Al Jazeera.
"It has resulted tragically in the death of one and the injury of two others."
Richard Miron, the UN spokesman, said the Israeli army had been notified in advance about the movements of the UNRWA convoy.
All convoys to Erez and the Kerem Shalom, which has been the main crossing point used for bringing humanitarian supplies into Gaza, were suspended after the incident.
"This underlines the fundamental insecurity inside Gaza at a time when we are trying to address the dire humanitarian needs of the population there," Miron said.
Al Jazeera’s Ayman Mohyeldin, reporting from Gaza City, said that 50 bodies were recovered during the three-hour lull, raising the death toll of Palestinians in Gaza to at least 763, including more than 200 children, since air raids first began on December 27.
More than 3,121 people have also been wounded. Eight Israeli soldiers and three civilians have died in the same period.
The Israeli military said it was looking into reports of Thursday’s incident.
A temporary halt in the nearly two-week Israeli offensive to allow humanitarian aid into the strip lasted from 1pm (11:00 GMT) to 4pm (14:00 GMT).
Explosions were heard in northern Gaza shortly after the period elapsed.
Israeli bulldozers crossed into Gaza during the lull and destroyed a number of houses, Al Jazeera’s Alan Fisher, reporting from southern Israel near the border, said.
Thousands of Palestinians fled their homes in the southern Gaza Strip as Israeli forces bombarded Rafah earlier on Thursday.
Homes, a mosque and tunnels were hit in the area along the Egyptian border, witnesses said.
The Israeli military had dropped leaflets beforehand warning it would "bomb the area due to its use by terrorists to [dig] tunnels and to stock up [on weapons]".
Hundreds of tunnels are believed to cross under the Egyptian border around Rafah allowing Palestinians to smuggle in basic supplies, in short supply due to the Israeli blockade, and weapons.
An Israeli army spokeswoman said the military had dropped the flyers "as in the past, to avoid civilian casualties".
Al Jazeera’s Ayman Mohyeldin, reporting from Gaza City, said the flyers would have frightened the civilian population of southern Gaza.
"Israel has cut the northern part of Gaza from the southern part. Those in the southern part wouldn’t be able to go to the north seeking refuge and vice versa," he said.
Mohyeldin said there was also another night of heavy bombardment in the north around Gaza City.
"Most of the targets hit throughout the northern part of the territory included mosques and homes that have been previously struck on the previous days of this conflict. Some of the government buildings and police stations that were nearly destroyed are now completely levelled," he said.
The AFP news agency quoted witnesses as saying that dozens of Israeli tanks had entered southern Gaza and were heading towards Rafah.
Fierce fighting was also reported between Palestinian fighters and Israeli soldiers around Khan Yunis.
It was unclear if the latest offensive was the "third stage" of the offensive approved by the Israeli security cabinet on Wednesday.
A senior Israeli defence official said a meeting chaired by Ehud Olmert, the prime minister, had "approved continuing the ground offensive, including a third stage that would broaden it by pushing deeper into populated areas".
The International Committee for the Red Cross (ICRC) on Thursday accused the Israeli military of not helping wounded Palestinians in an incident in Gaza City that it described as "shocking".
ICRC and Palestinian Red Crescent workers said in a statement that several wounded Palestinians and four weakened children were found alongside 12 dead bodies in houses hit by shelling in Zaytun, less than 100 metres from Israeli positions.
"The ICRC believes that in this instance the Israeli military failed to meet its obligation under international humanitarian law to care for and evacuate the wounded," it said.
The Red Cross team, including four ambulances, had only gained safe passage from Israeli army to access the neighbourhood on January 7 after trying for four days, the ICRC said.
Meanwhile, Israeli security forces in the occupied West Bank shot dead a Palestinian in a confrontation at a Jewish settlement near Jerusalem, Israeli radio reported.
(Aljazeera.net English and Agencies)