"That's our information," said a State Dept. official. "In the circumstances, it hardly comes as a surprise."
The White House, behind the scenes, is urging Abdullah to come, saying his absence will embarrass President George Bush.
"Abdullah cannot appear to be supporting a U.S. policy that isn't resulting in a cease-fire between Israel and the Palestinians, and there won't be a cease-fire," said Judith Kipper, Middle East expert at the Center for Strategic and International Studies in Washington.
A former senior diplomat to the region, who spoke on condition of anonymity, also said Abdullah's cancellation would be "a major error." But he faulted the administration: "We have a group in the White House that appears to have very little Middle East expertise."
According to State Dept. officials, Abdullah condemned Israel's massive offensive called "Operation Defensive Wall," a "savage act far from any human logic."
The Israeli government said the purpose of Operation Defensive Shield was to root out militants, citing the continued suicide bombings that have devastated Israel, especially the March 27 Passover suicide bombing that killed 28 people and injured 140 in a hotel in Netanya.
Hundreds of Palestinians have been killed since in the fierce offensive began, and much of the infrastructure of the West Bank destroyed.
Sunday, Abdel al Jubeir, foreign policy adviser to Abdullah, told CNN that Sharon's proposal for an international conference -- which the Israelis said, would move forward along the lines of the Saudi peace plan -- "would be a positive step if the Israelis were serious about a total withdrawal from the territories."
"I believe that the Palestinian Authority has made it very clear that they would support such an effort," he said. "Anything that can lead to a reduction in violence and to an end to the senseless killings would be welcomed by the international community.
The proposed conference would include Egypt, Jordan, Morocco -- and Saudi Arabia.
"The important thing here is deeds rather than words. We need a commitment from Israel to implement U.N. Resolution 1402, which is an immediate cease-fire and withdrawal from the territories," al Jubeir emphasized. "We have that commitment from the Palestinians, but we don't have it from Mr. Sharon."
Prior to Secretary of State Colin Powell's trip to Tel Aviv and Ramallah, Abdullah last week cautioned him that Israel's continuing military operations would endanger U.S. interests in the Arab world, according to U.S. officials.
When the Arab League summit met in Beirut March 27-28, Abdullah gave a keynote address that offered Israel "normal relations" in exchange for "full Israeli withdrawal" from Arab territories occupied in the 1967 Six Day War and "recognition of an independent Palestinian state with Jerusalem as its capital and the return of Palestinian refugees."
Abdullah then made a direct appeal to the Israeli people, pledging that if Israel gave up "the policy of force and suppression and accepts peace, we will not hesitate to accept the Israeli people's right to live in security with the rest of the region."
His speech won wide applause, and the Arab League adopted Abdullah's land-for-peace formulation unanimously and also approved a reconciliation between Iraq and Kuwait, which Abdullah, along with Egypt, helped to engineer.
Sharon began his full-scale assault to destroy the Palestinian Authority on March 29.
"Abdullah is hurt and humiliated," said a State Dept. official. "He made what he felt was a generous offer, only to see it entirely ignored, not just by Israel, but seemingly by the United States."
The former senior diplomat said: "The Abdullah Plan was the best thing to come out of Arabia in recent times. It's the best for the Arabs, best for Israel, and the best for the U.S."
According to former CIA Middle East operative, Bob Baer, Abdullah is a key player in U.S. Middle East policy. "He's our only hope for Saudi Arabia," he said. "He's the only guy willing to take on the corruption in the kingdom and fight the war on terror."
Baer said that it is corruption derived from huge military expenditures and grandiose developmental projects, and not land reform or women's rights or participatory democracy that is a key issue in Saudi Arabia. Ever since the aftermath of the Sept. 11 attacks disclosed that 15 of the 19 hijackers involved were Saudis, relations between the United States and the kingdom have been rocky.
"This is not a good development," Kipper said of the cancellation.