International Desk

Israeli forces pushed deep into the ruins of Gaza's northern edge on Monday to recapture an area from Hamas fighters, while in the south tanks and troops pushed across a highway into Rafah, leaving Palestinian civilians scrambling to find safety.

Some of the most intense fighting for weeks is raging in both the north and south. Israeli operations in Rafah, which borders Egypt, have closed a main crossing point for aid. Humanitarian groups say this has worsened an already dire situation.

Hundreds of thousands of people are fleeing again. Around half of Gaza's population took sanctuary there after Israel ordered evacuations from northern Gaza in October.

Gaza's health authority appealed for international pressure to reopen access via the southern border to allow in aid, medical supplies and fuel to power generators and ambulances.

"The wounded and sick suffer a slow death because there is no treatment and supplies and they cannot travel," it said.

A foreign UN security staff member was killed on Monday when a UN-marked vehicle travelling to a hospital in Rafah was struck - the first international UN fatality in the Gaza war, a UN spokesperson said, bringing the total death toll of UN personnel to around 190.

In northern Gaza's Jabalia, a sprawling refugee camp built for displaced Palestinians 75 years ago, Israeli forces pushed into an area where they claimed to have dismantled Hamas months ago.

Residents fled along rubble-strewn streets carrying bags of belongings. Tank shells landed in the centre of the camp and health officials said they had recovered 20 bodies from overnight airstrikes.Hamas' armed wing said its fighters were engaged in gun battles with Israeli forces in one of the streets east of Rafah, and in the east of Jabalia.

In Israel, the military sounded sirens several times in areas near Gaza, warning of potential Palestinian cross-border rocket and or mortar launches.

Israeli protesters blocked aid trucks headed for Gaza, strewing food packages on the road at Tarqumiya checkpoint, west of Hebron in the Israeli occupied West Bank.

Sullivan expressed concern about reports of Israeli settlers attacking a humanitarian aid convoy on its way to Erez Crossing in northern Gaza, the second such incident in less than a week.

"It is a total outrage that there are people who are attacking and looting these conveys," Sullivan said. "It is completely and utterly unacceptable behaviour."