The leaders of Britain, France, and Canada on Monday threatened action against Israel if it does not stop a renewed military offensive in Gaza and lift aid restrictions, piling further pressure on Prime Minister Benjamin Netanyahu.

The intervention comes after the Israeli military announced the start of a new operation on Friday, with Netanyahu saying earlier on Monday Israel would take control of the whole of Gaza. International experts have already warned of looming famine.

"The Israeli Government's denial of essential humanitarian assistance to the civilian population is unacceptable and risks breaching International Humanitarian Law," a joint statement released by the British government said. 

"We oppose any attempt to expand settlements in the West Bank ... We will not hesitate to take further action, including targeted sanctions."

Israel has blocked the entry of medical, food and fuel supplies into Gaza since the start of March to try to pressure Hamas into freeing the hostages taken by the Palestinian militant group on October 7, 2023, when it attacked Israeli communities.

"We have always supported Israel's right to defend Israelis against terrorism. But this escalation is wholly disproportionate," the three Western leaders said in the joint statement, adding that they will not stand by while Netanyahu's government pursues "these egregious actions."

They also stated their support for the efforts led by the United States, Qatar and Egypt for an immediate ceasefire in Gaza, and said they were committed to recognising a Palestinian state as a contribution to achieving a two-state solution.

The statement coincided with a joint demand by 22 countries -- including Britain, France and Canada -- for Israel to immediately "allow a full resumption of aid into Gaza", noting that the territory's population "faces starvation".

Israel has kept Gaza in a total aid blockade since March 2, but announced on Monday it would allow a limited number of supply trucks.

Prime Minister Netanyahu said the limited aid access was because "images of mass starvation" in Gaza could hurt the legitimacy of his country's war.

Gaza's health ministry said on Monday at least 3,340 people have been killed since Israel resumed strikes on March 18, taking the war's overall toll to 53,486.