BAGHDAD -- The Iraqi prime minister put his nation on its highest alert for terror attacks, as insurgents hammer Iraqi security forces preparing to take over for a U.S. combat mission that formally ends on Tuesday.

Prime Minister Nouri al-Maliki said Iraqi intelligence indicated that an Al Qaeda front group and members of Saddam Hussein's outlawed Baath party are collaborating to launch attacks "to create fear and chaos and kill more innocents."

"We direct the Iraqi forces, police and army and other security forces, to take the highest alert and precautionary measures to foil this criminal planning," al-Maliki said in a statement to state-run television on Friday night. He did not give details of the intelligence.

The alert was issued days before the Aug. 31 deadline for U.S. forces to end combat operations after seven years of war and transition to primarily training and advising Iraqi troops. American troops can still go on combat patrols with Iraqi soldiers and police if asked.

But the primary responsibility for protecting the nation is in the hands of an Iraqi security force that has largely failed to win the country's confidence.

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Insurgents have intensified attacks on Iraqi police and soldiers, making August the deadliest month for Iraqi security personnel in two years: On average, five were killed each day.

Civilians, too, are caught up in the attacks.

This week, bombers and gunmen killed at least 56 Iraqis in more than two dozen attacks across the country. More than half of the dead were Iraqi soldiers and policemen.

In a major embarrassment this month for Iraq's U.S.-trained forces, a suicide bomber was able to walk up undetected to an army recruitment station crowded with hundreds of applicants and kill 61 people. The Aug. 17 attack was the single deadliest act of violence in the capital in months.

In another sign of a stepped up campaign by insurgents, more than half of the 445 Iraqi security personnel killed this year -- including soldiers, police, police recruits and bodyguards -- died between June and August, according to an Associated Press count.

The prime minister seemed to recognize that security forces alone would not be able to stop the attacks, and he appealed to citizens to be vigilant.

"We call on the nation to have open eyes to monitor the movements of those terrorists and keep such criminal gangs from halting the progress of our nation."

Al-Maliki is locked in a power struggle to keep his job nearly six months after a parliamentary election that failed to produce a clear winner.

The political coalition led by al-Maliki, a Shiite, narrowly came in second place to a Sunni-backed alliance in the March 7 vote.

Iraq's political factions have been battling since to work out a power-sharing agreement. U.S. and Iraqi officials fear the political impasse could lead to increased violence.