Prime Minister Nouri al-Maliki met with Iraq's most influential Shiite cleric Saturday to discuss the country's deteriorating security situation, while attacks killed 13 Pakistani and Indian pilgrims south of the capital and three bombings that killed six people.

Al-Maliki met with Grand Ayatollah Ali al-Sistani in Najaf, 100 miles south of Baghdad, the cleric's office said. In July, al-Sistani was credited with restraining the Shiite community from widespread retaliation against minority Sunnis following horrific attacks on Shiite civilians.

"If the government does not do its duty in imposing security and order to the people and protecting them, it will give a chance to other powers to do this duty and this a very dangerous matter," al-Sistani's office quoted him as saying.

The meeting came two days after a barrage of coordinated attacks across mainly Shiite eastern Baghdad killed 64 people and wounded 286. Hundreds of Iraqis have been killed in violence this week, despite a massive security operation in the capital involving an extra 12,000 Iraqi and U.S. troops that has targeted some of Baghdad's most problematic neighborhoods.

On Friday, the Defense Ministry said security forces would expand the crackdown in a week to 10 days to the eastern parts of the capital, including Shiite militia strongholds.

Separately, authorities postponed a highly anticipated ceremony Saturday in which the Defense Ministry was to assume operational control of the country's armed forces from the U.S.-led coalition. The ceremony, which had been set to take place Saturday morning, was first delayed until later in the day, then postponed until Sunday.

Coalition spokesman Lt. Col. Barry Johnson said the reason was "miscommunication" in the timing of the ceremony.

Iraq's Defense Ministry and Joint Headquarters were to assume responsibility for the Iraqi Ground Forces Command, the Iraqi Air Force and the Iraqi Navy, U.S. authorities had said.

Handing over control from the coalition to Iraqi authorities is a key part of any eventual drawdown of U.S. troops in the country.

In Washington on Friday, the U.S. Defense Department issued a report to Congress saying sectarian violence is spreading in Iraq, with illegal militias becoming more entrenched, especially in Baghdad neighborhoods where they are seen as providers of security and basic social services.

Thursday's ferocious attacks in Baghdad centered on neighborhoods controlled by Shiite militias, some of which Sunni Arabs accuse of running death squads. Defense Ministry spokesman Muhammad Al-Askari said the planned expansion of the security crackdown in Baghdad would include those areas that were attacked.

"We have prepared everything, but we are waiting to mobilize the troops and prepare the special military units that will implement the raids," he said.

Sadr City, a stronghold of firebrand Shiite cleric Muqtada al-Sadr, would also be included, al-Askari told The Associated Press.

"No neighborhood is off limits," he said. "There's not a single neighborhood that's a red line for us. Any area that has terrorist activity, we will enter — there will be no stop sign."

Al-Askari said the first two phases of the operation, which included Sunni Arab districts, was successful. "The terrorists will not work in these districts any more, the terrorists are moving to suburbs of Baghdad, to districts that were not included in the first and second phases, to worsen the security situation there," he said.

In the latest violence, police said a group of 13 Pakistani and Indian pilgrims and their Iraqi driver were ambushed and killed on their way to the Shiite holy city of Karbala, 50 miles south of the capital. The pilgrims — 11 Pakistanis, including five women, and two Indians — were shot Friday, police said. They had all had their hands and legs bound.

Shiite pilgrims are to observe Shaaban, a mid-month religious celebration, on Sept. 9.

In Mahaweel, about 35 miles south of the capital, a car bomb exploded near a police station, killing three civilians and wounding 14, police Col. Ahmed Mejwel said.

In Baghdad, a car bomb exploded in the residential neighborhood of Waziriyah as a police patrol passed by, followed by a roadside bombing later at the same site, said police Maj. Ahmed al-Obeidi. Three people were killed.

The neighborhood is one of those which were to be included in the expanded security operation.