AMMAN, Jordan, Nov. 29 — Prime Minister Nuri al-Maliki of Iraq and King Abdullah II of Jordan cancelled a meeting with President Bush at the last minute today, against the backdrop of a radical Shiite cleric’s boycott of the Maliki government and the disclosure of a classified White House memo that was highly critical of Mr. Maliki.

Mr. Bush and Mr. Maliki are still scheduled to have breakfast together here Thursday morning, and to hold a much-anticipated joint press conference afterward.

But after meeting earlier today, Mr. Maliki and King Abdullah decided that a joint session planned for this evening with Mr. Bush was unnecessary, according to a senior White House official.

“The Jordanians and the Iraqis jointly decided they did not feel it was the best use of time” and notified Zalmay Khalilzad, the United States ambassador to Iraq, said the official, speaking on condition of anonymity. Mr. Khalilzad then called Air Force One to tell Mr. Bush and Secretary of State Condoleezza Rice, who were flying to Amman from Riga, Latvia.

Mr. Bush’s counselor, Dan Bartlett, told reporters that there turned out to be no need for the planned three-way session, since Mr. Maliki and King Abdullah had already met earlier in the day and Mr. Bush and King Abdullah were planning dine together privately later in the evening.

Mr. Bartlett said the cancellation had nothing to do with disclosure of the classified memo, reported in today’s issue of The New York Times. “No one should read too much into this, except for the fact that they had a good meeting,” Mr. Bartlett said, referring to Mr. Maliki and the king. (Related Article: Bush Aide’s Memo Doubts Iraqi Leader)

Meanwhile in Baghdad, lawmakers and cabinet members loyal to the anti-American cleric Moktada al-Sadr followed through today on a previous threat to boycott the government if Mr. Maliki went to Amman to meet with Mr. Bush. They said in a statement today that they were suspending their participation in both the parliament and the cabinet. (Related Article: Cleric’s Faction Boycotts Iraqi Government)

The lawmakers said they would resume participating only if the Iraqi government improves services to the general population and if it is given more oversight over the security forces.

Mr. Sadr controls one of the biggest blocs of seats in the Iraqi parliament. Last week he reiterated his claim that the American presence in Iraq was the root cause of rising violence. Mr. Maliki, a conservative Shiite, relies on Mr. Sadr for political support against rival Shiite leaders. President Bush’s hastily-planned trip to Jordan to see Mr. Maliki, tacked on to a swing the president made through the Baltics to attend a NATO summit, was intended to address the increasing level of violence in Iraq. Last week, more than 200 people died in a bombing in a Shiite district of Baghdad, the deadliest attack since the American invasion. A bloody reprisal followed.

At a press conference in Tallinn, Estonia, on Tuesday, Mr. Bush told reporters he intended to raise the subject of the bombings with Mr. Maliki. The president dismissed suggestions that Iraq was spiraling into civil war, and said Al Qaeda was to blame for the rising tide of sectarian violence.

“My questions to him will be: ‘What do we need to do to succeed? What is your strategy in dealing with the sectarian violence,’ ” Mr. Bush said, referring to the prime minister. “I will assure him that we will continue to pursue Al Qaeda to make sure that they do not establish a safe haven in Iraq.”

The cancellation of the evening meeting capped a day in which White House aides struggled to put a favorable spin on the classified memorandum, which was written by Stephen J. Hadley, the president’s national security adviser, after an Oct. 30 visit to Iraq to meet one-on-one with Mr. Maliki.

Mr. Hadley wrote in the memo that while the prime minister seems to have good intentions when talking with Americans, “the reality on the streets suggests Maliki is either ignorant of what’s going on, misrepresenting his intentions, or that his capabilities are not yet sufficient.”

Speaking this morning to reporters in Riga, Latvia, where the NATO summit was held, the White House press secretary, Tony Snow, insisted that Mr. Bush still has faith in Mr. Maliki.

“The president has confidence in Prime Minister Maliki,” Mr. Snow said.

He added that the administration “is working with the prime minister to improve his capabilities in terms of dealing with the fundamental challenges in Iraq.”

But it was clear that the White House was concerned about how Mr. Maliki might react to the document. Two senior administration officials, who insisted on anonymity in exchange for talking about a classified memo, said it was unclear whether Mr. Maliki had seen the document.

Despite the memo’s suggestion that the prime minister may be ignorant of what is going on, or misrepresenting his intentions, the officials insisted that the president believes Mr. Maliki is well-intentioned but in need of help figuring out how to tamp down the sectarian violence, so that Iraqis can assume a greater role in their own security.

“The judgment is that it’s a capability issue,” one official said.

Reporting for this article was contributed by Edward Wong from Baghdad, Christine Hauser from New York, and Hassan M. Fattah from Amman, Jordan