US President Joe Biden has discussed the Israel-Hamas war with leaders of major Western powers, the White House said, as Israel intensified its attacks on Gaza.

Biden spoke with the leaders of Britain, Canada, France, Germany and Italy, the White House said.

"The leaders reiterated their support for Israel and its right to defend itself against terrorism and called for adherence to international humanitarian law, including the protection of civilians," a White House readout of the discussions said.

It said the leaders discussed their own citizens trapped in the Israel-Hamas war, "in particular those wishing to leave Gaza."

In a joint statement, the leaders also welcomed the release of two hostages and called for the immediate release of all remaining hostages.

Hamas militants stormed across the border into Israel on October 7, launching a raid that killed at least 1,400 people, according to Israeli officials. They also seized more than 200 hostages in the worst attack in Israel's history.