AMMAN, Jordan, Nov. 29 — Prime Minister Nuri Kamal al-Maliki of Iraq and King Abdullah II of Jordan abruptly backed out of a meeting with President Bush on Wednesday, leaving the White House scrambling to explain why a carefully planned summit had suddenly been cut from two days to one. The decision occurred on a day that a classified White House memo expressing doubts about Mr. Maliki was disclosed and after Iraqi officials loyal to a powerful Shiite cleric said they were suspending participation in the Maliki government because he had ignored their request to cancel the Bush meeting. The president and Secretary of State Condoleezza Rice were already aboard Air Force One, on the way to Amman from Riga, Latvia, where they had been attending a NATO summit, when they received the news by telephone from the United States ambassador to Iraq, Zalmay Khalilzad. The White House insisted Mr. Bush was not upset and had not been snubbed. “Absolutely not,” said Dan Bartlett, counselor to the president.