The shift came after Mr. Maliki made several last-ditch efforts to shore up support, only to be confronted late Monday night with delegations of officials, all pleading with him to back down for the good of the country.

The next morning, an important Iraqi Army general in Baghdad reached out to Iraq’s new president, Fuad Masum, and the man he nominated to be the next prime minister, Haider al-Abadi, and delivered the message that the military would not stand by Mr. Maliki, according to a senior Iraqi official.

Hours later, Mr. Maliki’s office released a statement that reflected both the growing opposition to him and the reality that the military probably would not back him anyway, if he tried to mount a coup: “Prime Minister Maliki urges commanders, officers and individuals to stay away from the political crisis and to commit to their military and security duties and tasks to protect the country, and not to intervene in this crisis. Leave this issue to the people, politicians and justice.”