The United States, the United Nations, the European Union and Russia have urged Israel "to halt immediately" its military operations, UN chief Mr Kofi Annan said.
Mr Annan was speaking at a press conference held in Madrid with US Secretary of State Mr Colin Powell, senior EU officials and Russian Foreign Minister Mr Igor Ivanov.
Mr Annan said the four parties, known as "the quartet", had called in a statement for "Israel to halt immediately its military operations."
The four also urged immediate application of UN resolutions 1402 and 1403 calling for a ceasefire and an end to violence and attacks, he said.
The UN chief stressed before reading the joint statement that he was "frankly appalled" by the humanitarian crisis caused in the Palestinian territories by the Israeli offensive.
Mr Powell is flying on to Jordan tomorrow, then to Jerusalem to begin efforts to reach a ceasefire between the Israelis and Palestinians.
He said he expected Israel to withdraw its troops from the West Bank. He is also called on Arab nations, particularly Syria and Iran, to clamp down on militant groups.
Mr Powell is pressing for negotiations to establish a Palestinian state and said Washington would seek a swift end to violence between the two sides.
Setting no deadline to complete his mission, Mr Powell said he would meet Palestinian leader Mr Yasser Arafat as well as Israeli Prime Minister Mr Ariel Sharon to attempt to broker a truce. "I have not set any departure date," the secretary of state said. "I am prepared to stay for some while."
Mr Powell raised the possibility of the US State Department providing a small number of civilian observers to monitor a ceasefire, if one was to be reached.
AP, AFP