By Andrew Gray

WASHINGTON, Feb 1 (Reuters) - Army Gen. David Petraeus, the U.S. commander in Iraq, has not asked for a pause in the withdrawal of forces after the pullout of some 20,000 troops by this summer, the top U.S. military officer said on Friday.

Petraeus said in a CNN interview aired last Sunday he would need some time to "let things settle a bit" after the initial drawdown, prompting speculation he wanted to keep about 130,000 troops or more in Iraq well into the second half of the year.

But Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, said it was too soon to say what Petraeus or Ryan Crocker, the U.S. ambassador in Iraq, would recommend when they come to Washington in April to provide an update on the war.

"Neither he or Ambassador Crocker have made any specific recommendations about future force levels in Iraq," Mullen told reporters at the Pentagon.

On the question of whether Petraeus favored a pause, Mullen said, "He's given no indication to anybody in the chain of command that that's where he is."

President George W. Bush ordered about 30,000 extra troops into Iraq last year to curb rampant violence that brought Iraq to the brink of all-out civil war and made the conflict deeply unpopular in the United States.

With violence now down significantly, the United States plans to have withdrawn five combat brigades and some other units -- a total of about 20,000 troops -- by mid-July.

Defense Secretary Robert Gates has said he hopes drawdowns can continue at the same pace in the second half of the year.

The current drawdown plan would leave about 137,000 U.S. troops in Iraq -- around the same level as in early 2007, before Bush ordered the troop increase.

Troop levels in Iraq are a big U.S. political issue, particularly in a presidential election year. Democrats want a swift withdrawal, while Republicans have said U.S. commanders should decide when it is safe to pull out.

The troop levels are also an important consideration for the U.S. military service chiefs, who have seen their forces severely strained by the wars in Iraq and Afghanistan. Any drawdown in Iraq could reduce that strain.

Gates asked the Joint Chiefs and Adm. William Fallon, the top U.S. commander for the Middle East, to present their own views on troop levels in Iraq at the same time as Petraeus gives his assessment.

"I'm very confident that there's a terrific process in place," Mullen said. "I think we need to have some patience to let it work and not presume the answers."

Army Brig. Gen. Joseph Anderson, chief of staff of the U.S.-led Multi National Corps-Iraq, said the performance of Iraqi security forces as they take more responsibility would be key in any decision to pull out more U.S. troops.

"The comfort level -- watching how successful they are in doing that -- will be a huge determining factor in how much faster and at what pace we should go further down from this summer," he told Pentagon reporters by videolink from Iraq. (Additional reporting by Kristin Roberts; Editing by Peter Cooney)

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