FORWARD OPERATING BASE FALCON, Iraq — Defense Secretary Gates today endorsed, for the first time, the idea of pausing the drawdown of America forces from Iraq this summer.

“A brief period of consolidation and evaluation probably does make sense,” Mr. Gates told reporters after meeting with the top American commander in Iraq, General David Petraeus. General Petraeus has indicated in recent weeks that he wants a “period of evaluation” this summer to assess the impact on Iraq security of reducing the American military presence to 15 brigades from 20 brigades.

Of that five-brigade reduction, only one has departed thus far. The last of the five is to be gone by the end of July.

In his remarks at an American base in southern Baghdad, Mr. Gates said General Petraeus had given him his view on the drawdown, which some fear could result in giving up some of the security gains of recent months.

In endorsing General Petraeus’s suggestion of pausing after July, Mr. Gates made it clear that President Bush would have the final say. Until now it had been unclear how Mr. Gates felt about the idea of a pause; he had said publicly a number of times that he hoped conditions in Iraq would permit a continuation of the drawdown in the second half of the year.

In his remarks here, Mr. Gates indicated that he had begun some time ago to lean in General Petraeus’s direction.

“In my own thinking I had been kind of headed in that direction as well,” Mr. Gates said. “But one of the keys is how long is that period (of pause and evaluation) and then what happens after that.”

Although General Petraeus and other senior commanders in Iraq had been suggesting the possibility of a pause in the drawdown, the idea runs counter to those in the military — particularly in the Army and Marine Corps — who worry that strains on troops from long and multiple combat tours will grow worse unless the drawdown continues after July.

Meantime, police and hospital officials said that twin car bombs struck near the compound of one of Iraq’s most powerful Shiite politicians, killing at least six civilians and wounding 20. A dense cloud of black smoke rose over the offices of Abdul-Aziz al-Hakim, the leader of the country’s largest Shiite party, the Supreme Islamic Iraqi Council, or SIIC. More than dozen cars were destroyed in a blackened area, and a brick building was blown apart.

The Gates traveling party was not affected. In a ceremony earlier at Camp Victory, the secretary presented the no. 2 commander in Iraq, Lieutenant General Ray Odierno, with a Defense Distinguished Service Medal for his accomplishments in Iraq.

Mr. Gates said that General Odierno, working under General Petraeus, “combined classic counterinsurgency with approaches that broke new ground in the history of warfare.” Mr. Gates recalled that when General Odierno took command in December 2006, conditions in Iraq were described by some as a civil war.

“Those early months were tough times,” Mr. Gates said. “Casualties were high. There were questions in the United States and around the world whether this new strategy — or any strategy, for that matter — would be able to make a real difference. What a difference you made, and much more — Al Qaeda routed, insurgents co-opted, levels of violence of all kinds dramatically reduced.”

Still, Mr. Gates said, “The situation in Iraq continues to remain fragile.”

General Odierno is departing after 15 months in charge of the headquarters that carries out General Petraeus’s strategy on a day-to-day basis. General Odierno is returning to Washington and has been nominated by President Bush for promotion to four-star rank and assignment as Army vice chief of staff.

Yesterday, Mr. Gates said Iraq’s political leaders face hard choices on how to stabilize the country despite promising new signs of progress toward reconciliation.

“They seem to have become energized over the last few weeks,” Mr. Gates said. The Pentagon chief told reporters who traveled with him from a conference in Germany that he wants to “see what the prospects are for further success in the next couple of months.”

It was Mr. Gates’s first visit this year and possibly his last before General Petraeus and the American ambassador, Ryan Crocker, return to Washington in April to recommend to Mr. Bush whether to continue reducing American troop levels after General Petraeus’s current drawdown plan is completed in July.

The question is whether conditions in Baghdad and elsewhere have improved enough to permit even more troop cuts without risking a deterioration in security. General Petraeus’s strategy is based on an expectation that improved security over time will give Iraqi political leaders an impetus to make compromises on legislation and other moves toward reconciliation.

In an interview with reporters traveling with Mr. Gates, the commander of all American forces in Baghdad, Major General Jeffery Hammond, declined to say how many troops he would be losing during the drawdown, saying he believed that information was secret. But he said that whatever troop-cut decisions are made, he will make the necessary adjustments to ensure that the security gains achieved over the past several months are not sacrificed.

“We’re not going to give back any terrain,” General Hammond said.

Before Mr. Gates’s arrival, the American military said a diary and another document seized during raids showed that some Al Qaeda in Iraq leaders fear the terrorist group is crumbling and that many fighters are defecting to American-backed neighborhood groups.