One hundred fifty trucks carrying humanitarian relief supplies and fuel entered the Gaza Strip through the Rafah crossing on Friday as part of a hostage exchange deal between Israel and Hamas.

Four of the trucks were loaded with cooking gas and three with fuel, according to the authorities in Gaza.

Humanitarian aid has begun flowing into the Gaza Strip in larger quantities following the start of a pause, with long truck convoys on the move, a spokesman for the U.N.'s Office for the Coordination of Humanitarian Affairs (OCHA) said in Geneva.

Before the war, around 500 trucks carrying aid passed into the region daily, but since mid-November, the number has declined to a few dozen. On Thursday, the figure rose to 80, according to the OCHA.

The spokesperson said trucks were queuing at the Rafah crossing on the border with Egypt. When they would be allowed to cross was out of OCHA's hands, he said. Israel insists on inspecting the loads for weapons and other war materials.

He was unable to say whether any aid would reach the northern part of the Gaza Strip, where Gaza City lies and where hundreds of thousands of Palestinians are holding out despite Israeli calls for them to leave. Still, he noted that the OCHA constantly talked with all parties to the conflict.

The World Health Organization (WHO) aims to use the truce to evacuate more patients from hospitals in the north. "We are extremely concerned about around 100 patients remaining in Shifa Hospital," a spokesperson said in Geneva.