The World Health Organization is calling on Israel to agree to a ceasefire in the Gaza Strip, saying that children there are dying of starvation.

WHO Director-General Tedros Adhanom Ghebreyesus revealed in his social media post on Monday that staff members visited northern Gaza over the weekend.

He said the only pediatrics hospital in the area is overwhelmed with patients. He said: "The lack of food resulted in the deaths of 10 children. The lack of electricity poses a serious threat to patient care, especially in critical areas like the intensive care unit and the neonatal unit."

He also said: "The key medicine all these patients need is peace. Ceasefire."

US Vice President Kamala Harris met former Israeli Defense Minister Benny Gantz, who is a member of the country's war Cabinet, in Washington on Monday.

The White House says Harris expressed her deep concern about the humanitarian conditions in Gaza, and discussed the urgency of achieving a hostage deal. She also reportedly urged Israel to take additional measures to increase the flow of humanitarian aid into Gaza.

In her speech on Sunday, Harris bluntly called on Israel to do more to increase the flow of aid. Reuters news agency says "her comments reflected intense frustration, if not desperation, within the US government about the war."

There have been no reports so far on progress in the on-going negotiations in Egypt for a pause in the fighting between Israel and the Islamic group Hamas, and the release of hostages.