Palestinian and Israeli leaders appealed for support at a UN Security Council session on Sunday but little action was in sight despite soaring violence, with China accusing the US of blocking.
After a delay pushed by the US, Israel's major ally, the council held its first public meeting on nearly a week of violence that has killed 192 Palestinians, including at least 58 children, and 12 Israelis.
Opening the online session, UN Secretary General Antonio Guterres called the violence "utterly appalling" and urged Palestinian militants Hamas to stop firing rockets into Israel and for Israel to halt its intensive air campaign on the Gaza Strip.
"Fighting must stop. It must stop immediately," Mr Guterres said.
"It has the potential to unleash an uncontainable security and humanitarian crises and to further foster extremism, not only in the occupied Palestinian territory and Israel, but in the region as a whole."
Palestinian Foreign Minister Riyad Al Maliki accused Israel of "war crimes" because of the heavy toll on civilians.
"Act now to end the aggression and the assault on our people, our homes, our land," Mr Al Maliki said. "Act now so freedom can prevail, not apartheid."
Hamas, which rules the Gaza Strip, began firing rockets after Israeli troops entered Al Aqsa Mosque compound in Jerusalem, the third-holiest site in Islam, after moves to expel Palestinians from their homes in the city's east to make way for Jewish settlers.
Mr Al Maliki, who is part of the Palestinian Authority that runs the West Bank, said that Israel could not expect to "bear no consequences" for its actions as an "occupying colonial power".
Speaking later, Israel's ambassador to the UN, Gilad Erdan, said the tension was "completely premeditated" by Hamas as part of an internal power play after the Palestinian Authority delayed long-awaited elections.
"Do you really believe that this property dispute is what caused Hamas to launch these large-scale attacks on the people of Israel?" Mr Erdan said.
He urged the Security Council to condemn Hamas, saying Israel "makes every effort to avoid civilian casualties".
Mr Erdan praised the support of the US, where President Joe Biden has repeatedly defended what he says is Israel's right to self-defence.
China, which holds the rotating presidency of the Security Council, said the US had blocked its efforts for "strong action". It invited Israelis and Palestinians to negotiate in Beijing.
"Regrettably, simply because of the obstruction of one country, the Security Council hasn't been able to speak with one voice," Foreign Minister Wang Yi said.
"We call upon the United States to shoulder its due responsibilities."
Linda Thomas-Greenfield, the US ambassador to the UN, stopped short of insisting on an immediate ceasefire.
Ms Thomas-Greenfield said the Biden administration was in touch with all sides including Qatar, which has close ties with Hamas, and Egypt, which has a peace deal with Israel and shares a border with Gaza.
"The United States has made clear that we are prepared to lend our support and good offices should the parties seek a ceasefire," she said.
"We believe Israelis and Palestinians equally have a right to live in safety and security."
Mr Biden succeeded Donald Trump, who was also a backer of Israel.
The Republican Party had already accused Mr Biden of not doing enough for Israel.
