"The clock is ticking," Gates told reporters, saying he will warn Iraqi officials that they must move faster on political reconciliation. "I know it's difficult, and clearly the attack on the council of representatives has made people nervous, but I think that it's very important that they bend every effort to getting this legislation done as quickly as possible."
A suicide bomber infiltrated the parliament building in the fortified Green Zone a week ago, dealing a blow to the U.S.-led effort to pacify the capital's streets.
Prime Minister Nouri al-Maliki called the violence in Baghdad an "open battle."
Gates, traveling to Iraq for the third time in four months, took a decidedly stronger tone this time, reflecting U.S. frustration and the political tumult in Washington, where President Bush and Congress are deadlocked over whether to set an end date for the war.
Since January, when Bush announced his new strategy for the Iraq war - featuring a troop buildup and a renewed push for economic development and political progress - Gates and other senior administration officials have frequently and publicly reminded the Iraqis that they must act quickly to settle their differences. They have attempted to strike a balance between pressuring the Iraqis to reconcile and reassuring them that the U.S. military will not abandon them while they struggle to avert a full-scale civil war.
Gates said again Thursday that the Washington debate has been helpful in letting the Iraqis know that American patience with the war is ebbing. Democrats have seized on those remarks to bolster their arguments that there must be a deadline for the Pentagon to begin withdrawing troops from Iraq.
The last time a U.S. defense secretary visited Fallujah - which until late 2004 was a key stronghold of the Sunni insurgency - it was Donald H. Rumsfeld, who stopped here in December 2005 to announce a plan to begin reducing U.S. troops. Small reductions were made, but shortly afterward troop levels began climbing again. In February 2006, the spectacular bombing of a mosque in Samarra, north of Baghdad, set off a wave of sectarian retribution and a surge of civilian deaths that scuttled U.S. plans to pull out more troops.
Gates said the Iraqis must, as quickly as possible, push through legislation on political reconciliation and the sharing of oil revenues among the Sunnis, Shiites and Kurds.
"It's not that these laws are going to change the situation immediately, but I think ... the ability to get them done communicates a willingness to work together," he said.
Those efforts, Gates said, would, in turn, create an environment in which violence could be reduced. But he acknowledged, "I'm sympathetic with some of the challenges that they face."
Shortly after landing in Baghdad, Gates boarded a helicopter to Camp Fallujah, about 35 miles west of the capital city. There, he met with top military commanders, including Joint Chiefs Chairman Gen. Peter Pace, and the top U.S. commander in Iraq, Army Gen. David Petraeus. Commanders agreed that the recent uptick in violence is troublesome, occurring just as they were starting to see some improvements. Gates stopped in Iraq on a trip through the Middle East. His visit comes on the heels of Iraq's bloodiest day since the U.S. troop buildup ordered by Bush began nine weeks ago. On Wednesday, four bomb blasts killed 230 people. "Yesterday was a bad day, there's no two ways about it," said Petraeus. "And a day like that can have a real psychological impact, and it came at a time where frankly ... (we) felt like we were getting a bit of traction." Petraeus added that while the changes are almost imperceptible at times, there had been slow progress both in Anbar Province, which has been a stronghold for Sunni insurgents, and with the Baghdad security plan. "Clearly these sensational attacks can't be anything other than viewed as setbacks and challenges," said Petraeus. But he said that after meeting with Iraqi leaders Wednesday and Thursday, he believes they are determined to calm their people and press on. Commanders also expressed little support for withdrawing troops in the coming months. Brig. Gen. Mark Gurganus, commander of ground forces in Anbar Province, said he has seen progress in western Iraq, including a decrease in attacks and an increase in recruitment of Iraqi police and army soldiers. Reducing his forces, he said, could erase the gains they've made. "Would it have an adverse impact? Absolutely," he said. Underscoring the urgency in controlling the violence, police said a suicide car bomber rammed into a fuel truck in central Baghdad only hours before Gates arrived, killing at least a dozen people. "It is very important they make every effort to get this done as soon as possible," Gates said, noting that the attack at the Iraqi parliament building made people particularly nervous. Just a day before Gates' visit, Bush met with congressional leaders to discuss the impasse over legislation to provide funds for the war effort in Iraq and Afghanistan. Three of the five brigades Bush ordered into Iraq to stem Baghdad violence have arrived, bringing U.S. forces in the country to 146,000. Officials want the rest in place by June, for a total of 160,000. Soon after that, they plan to assess how much longer the higher troop level - about 30,000 more than before the buildup - will be needed. Officials have struggled to find troops from within the stretched U.S. military to sustain the increase. Gates last week lengthened tours of duty to the war zones in Iraq and Afghanistan from one year to 15 months.