A World Health Organization mission reached the north of Gaza for the first time in more than two weeks, WHO chief Tedros Adhanom Ghebreyesus said on Wednesday.

The mission delivered fuel, hospital beds, medicines and other medical supplies to the Al-Ahli hospital, Tedros announced on X.

"Amid ongoing intense hostilities, @WHO and partners still managed to reach Al-Ahli Hospital in #Gaza city. First mission to the north of the Strip since 13 May," said Tedros.

He said the supplies were enough to cover the needs of 1,500 people but insisted that much more was needed.

"Al-Ahli hospital is serving twice the number of people it is designed for, lacking essential surgical supplies, and salaries for the staff," said Tedros.

"No lifesaving surgery can be performed in the evening due to the lack of specialised staff."

Tedros said the WHO was trying to deploy "an emergency medical team" there.

The WHO delivered 15,000 litres of fuel -- which is essential for the generators that produce the hospital's electricity -- 14 hospital beds, medicines and trauma supplies.

The mission also escorted five ambulances from the Palestinian Red Crescent society to the north of the territory.

However, it was unable to reach a second hospital due to delays at a checkpoint.

Missions to the north of Gaza have been complicated by the bombardment of the territory by Israeli forces since the Islamist Hamas movement launched its attack on Israel last October.

Aid missions lack fuel for vehicles while many roads have been destroyed, Tedros said, renewing his calls for a ceasefire in the war.

Close to 1,200 people, mostly civilians, were killed in the Hamas attack on October 7, according to an AFP tally based on the latest Israeli official figures.

Israel's retaliatory offensive has killed more than 36,000 people in Gaza, mostly civilians, according to the Hamas-run health ministry.