US President Joe Biden has voiced his support for a ceasefire after eight days of violence between Israel and Palestinian militants in Gaza.
Mr Biden told Israeli Prime Minister Benjamin Netanyahu that the US was working with Egypt and other countries on halting hostilities.
But the US again blocked a UN Security Council statement calling for a cessation of violence.
The conflict is now in its second week, with little sign of ending.
Israel conducted further air strikes on Gaza early on Tuesday. Its army said dozens of rockets were fired into its territory overnight.
At least 212 people, including almost 100 women and children, have been killed in Gaza, according to its health ministry. In Israel 10 people, including two children, have been killed, its medical service says.
On Tuesday Israel said at least 150 militants were among those killed in Gaza. Hamas, the Palestinian militant group that runs the territory, does not give casualty figures for fighters.
According to a White House statement on Monday, Mr Biden "encouraged Israel to make every effort to ensure the protection of innocent civilians".
"The two leaders discussed progress in Israel's military operations against Hamas and other terrorist groups in Gaza," it added.
President Biden "expressed his support for a ceasefire and discussed US engagement with Egypt and other partners towards that end", it said.
The violence has prompted increasing concern internationally.
World leaders and humanitarian organisations have called for measures to prevent the deaths of residents and the chaos wrought by the destruction of buildings and infrastructure.
The US - which is one of Israel's strongest allies - has once again blocked efforts at the UN Security Council to issue a statement calling on Israel to stop its military offensive, stressing instead its own diplomatic efforts.
"Our calculation at this point is that having those conversations behind the scenes... is the most constructive approach we can take," White House spokeswoman Jen Psaki told reporters.
The UN Security Council is due to hold its fourth emergency meeting on the violence on Tuesday.