King Abdullah of Jordan has postponed talks with US President George W Bush on Wednesday amid concern over America's support for Israeli policy.
King Abdullah has been visiting the US
Jordan announced that it needed time to "clarify the US position" on the Middle East peace process.
A BBC correspondent says the move is something of a diplomatic snub.
At the United Nations Arab states have urged the Security Council to condemn Israel's targeted killings policy after the death of the leader of Hamas.
Jordan's snub comes just after Mr Bush broke with long-standing American policy and acknowledged that Israel would keep many of its settlements in the West Bank and follows the killing of Abdel Aziz al-Rantissi on Saturday in Gaza.
King Abdullah walks a delicate line among his Arab neighbours, seeking to maintain a position of even-handedness in the turbulence of the Middle East, Adam Brookes reports from Washington.
Jordan is one of Washington's main allies in the region and has signed a peace deal with Israel.
At a moment when the Israelis appear to have more influence with the Bush administration than they have had in a long time, it seems the king feels this just is not the time to be seen walking America's corridors of power, our correspondent adds.
King Abdullah's meeting with Mr Bush has tentatively been rescheduled for the first week of May, US and Jordanian
A vote is expected in the UN Security Council on Tuesday after the Arab states submitted a draft resolution calling for Israel to end extra-judicial executions, though not mentioning Rantissi by name.
Hamas supporters continue to mourn their dead leader
Palestinian representative Nasser al-Kidwa said the assassination was the latest in a long series of war crimes and the Security Council's failure to condemn Israel had encouraged it to continue.
Israeli envoy Dan Gillerman called Rantissi a radical terrorist leader and he defended his killing, saying there had been no viable means of arresting the Hamas leader.
"It is no good to affirm in theory Israel's right to defend itself in this conflict but then in practice seek to deny us the right to specifically target those illegal combatants directly responsible," he said.
Three weeks ago, the US vetoed a resolution condemning Israel for killing Rantissi's predecessor, Sheikh Yassin.
The BBC's UN correspondent, Susannah Price, reports that it appears likely any similar resolution will also be vetoed by America.
Hamas's political leader, Khaled Meshaal, has called for an Arab-Muslim alliance to defeat the US and Israel.
"Our battle is with two sides, one of them is the strongest power in the world, the United States, and the second is the strongest power in the region [Israel]," he told a crowd at the al-Yarmouk Palestinian refugee camp near the Syrian capital, Damascus.