Iraq's prime minister appeared Monday to have succeeded — with a last-minute push from the U.S. ambassador — in pulling together a crisis council this week to save his crumbling government.

The U.S. military, meanwhile, announced a third major operation since additional U.S. troops arrived and said it would target Al Qaeda in Iraq and Iranian-allied Shiite militia fighters nationwide. The military gave few other details.

The meeting among Prime Minister Nouri al-Maliki, the three-man Presidency Council and the leader of the autonomous Kurdish region was intensely negotiated over the past several days.

And the summit appeared slated for Tuesday after U.S. Ambassador Ryan Crocker called on Vice President Tariq al-Hashemi, the lone Sunni Arab invited to the talks. Until the Monday meeting, al-Hashemi's attendance had been in question.

A senior American official, who spoke in Baghdad, said the stage was set for major changes in the "structure, nature and direction of the Iraqi state." The official spoke on condition of anonymity because of the delicate nature of the summit.

On the eve of the session, the 40 seats in al-Maliki's Cabinet were nearly half empty after a series of resignations and boycotts. Critical legislation demanded by the prime minister's American patrons has languished for months with no promise of movement — even as the top two American officials here faced a mid-September deadline to report to Congress on progress in Iraq.

Crocker and U.S. commander Gen. David Petraeus were expected to begin Congressional testimony the week of Sept. 10.

The tangled thicket of Iraqi politics defies linear explanations. But with confusing details stripped away, al-Maliki, a religious Shiite, was expected to try to co-opt al-Hashemi, a moderate Sunni, with promises of a greater say in decision-making. There was the possibility as well that the Iraqi leader would give ground on Sunni demands for the release of prisoners being held without charge.

If al-Maliki were able to bring al-Hashemi on board — which remained uncertain — he then could tell Sunni Cabinet ministers who quit the government earlier this month that they were welcome back under the new agreements.

Should they refuse, al-Maliki has said he was ready to name Sunnis from outside their political bloc to the vacant cabinet positions. He even mentioned reaching out to Sunni tribal aheiks in Anbar province, where the Sunni insurgency was born.

Parliament-watchers have figured that al-Maliki could marshal sufficient votes to win approval of the new nominees. That move would essentially sideline the largest Sunni bloc which ordered the resignations in the first place. While al-Hashemi is a member of the bloc, he refused to resign his vice presidency.

If al-Hashemi were to join in a new pact with al-Maliki, President Jalal Talabani, a Kurd; the Shiite Vice President Adil Abdul-Mahdi, and Kurdish region leader Massoud Barzani, the disaffected Sunni bloc, the Accordance Front, could be left with a much diminished political voice in the executive and head-of-state branches of government.

Al-Hashemi, as a member of the Presidency Council with Talabani and Abdul-Mahdi, had been able to block key legislation from reaching parliament.

The Iraqi constitution calls for unanimous approval by the council before important legislation is sent to lawmakers for approval. Al-Hashemi was said to have been the holdout against much of the U.S.-sought benchmark legislation — such as the oil law and the law that would rehabilitate some lower-ranking members of Saddam Hussein's Baath Party.

But reaching such a deal was expected to test al-Maliki's willingness to accommodate the Sunni demands for prisoner releases, a greater say in government and more attention to problems of the Sunni minority that had run the country and heavily oppressed Shiites for more than three decades.

The senior U.S. official said the meeting could re-energize political reconciliation.

"This isn't a one-off kind of thing," the official said. "A lot of this is developing mechanisms which can be used, not instant solutions but understandings that the solutions are going to be needed over time. And making a commitment to a mechanism, a process and keeping at that process until Iraq is in a better place."

He said Crocker would be available for consultations if needed but would not participate in the meetings, which the official called an Iraqi initiative.

The U.S. military named its new offensive "Operation Phantom Strike" and said it would seek to build on the successes of recent offensives in Baghdad and surrounding areas.

The statement singled out Sunni insurgents linked to al-Qaida in Iraq and Shiite extremists the U.S. military claims are backed by Iran. The military has stepped up its rhetoric against Tehran, saying it supplies the militants with arms and training to attack U.S. forces. Iran denies the allegations.

The military statement did not give details but said U.S. forces would increase pressure on al-Qaida and its Sunni militant allies and rogue Shiite militiamen nationwide. Many of those fighters have fled the six-month-old crackdown in Baghdad and central Iraq and were believed trying to set up bases of operation father afield.

"My intent is to continue to pressure AQI and other extremist elements throughout Iraq to reduce their capabilities," said Lt. Gen. Ray Odierno, the U.S. second-in-command.

Iraqi judicial authorities also said the third trial against former officials with Saddam Hussein's ousted regime would begin on Aug. 21. Saddam's cousin Ali Hassan al-Majid, known as "Chemical Ali," and 14 other defendants will face charges in the brutal crushing of a Shiite uprising after the 1991 Gulf War.