Using charts to make his points, the four-star general said civilian deaths have declined by more than 40 percent since December 2006, and car bombings and suicide attacks are also down, although the numbers are still at "troubling levels."
But the U.S. military has made "substantial progress against Al-Qaeda and its affiliates in Iraq," and Iraqi security forces are becoming stronger and taking on more responsibility, he said.
"Iraqi security forces have also continued to grow and to shoulder more of the load, albeit slowly and amid continuing concerns about the sectarian tendencies of some elements in their ranks," Petraeus said. "In general, however, Iraqi elements have been standing, and fighting, and sustaining tough losses, and they have taken the lead in operations in many areas."
First U.S. Troops Out By End Of 2007
The U.S. commander said things are going well enough that troop numbers can be brought back to pre-surge levels -- about 130,000 -- by next summer. The addition of 30,000 soldiers this summer brought the current number of U.S. troops in Iraq to 168,000.
But Petraeus warned that a premature withdrawal of U.S. forces could have "devastating effects" and he urged lawmakers against even setting a deadline to make a decision.
"I do not believe it is reasonable to have an adequate appreciation for the pace of further reductions and mission adjustments beyond the summer of 2008 until about mid-March of next year," he said.
In Baghdad, Iraqi government spokesman Ali al-Dabbagh responded to Petraeus’ comments by saying that Iraq would be comfortable with a gradual withdrawal of U.S. troops as long as it was first discussed with the Iraqi government.
Crocker 'Disappointed' But Hopeful
Following Petraeus's testimony, U.S. Ambassador to Iraq Ryan Crocker testified on the political situation in Iraq and sounded cautiously optimistic that the country can achieve peace within its borders and within the region.
"A secure, stable, democratic Iraq at peace with its neighbors is, in my view, attainable," he said. "The cumulative trajectory of political, economic, and diplomatic developments in Iraq is upwards, although the slope of that line is not steep."
Crocker acknowledged that he himself was disappointed at the slow pace of progress by the Iraqi government on legislative benchmarks, but he pointed out that slow progress is not the same as no progress, and reminded the committee the military surge didn’t reach full strength until June.
"Our country has given a great deal of blood and treasure to stabilize the situation in Iraq and help Iraqis build institutions for a united, democratic country governed under the rule of law," he said. "Realizing this vision will take more time and patience on the part of the United States."
The top U.S. diplomat in Iraq also told lawmakers that Iran will achieve a measure of victory if the United States abandons the fight in Iraq. In his meetings with Iranian officials on Iraqi stability issues, Crocker said, he came away unconvinced that Iran was sincere in its desire to help. The Islamic republic will try to consolidate its power and influence if Iraq is allowed to fall into chaos, he warned.
"The impression I came away with after a couple of rounds [with Iranian negotiators] is that the Iranians were interested simply in the appearance of discussions, of being seen to be at the table with the U.S. as an arbiter of Iraq's present and future rather than actually doing serious business," Crocker said.
Before Petraeus's appearance in Congress, Anthony Cordesman, an analyst at the Center for Strategic and International Studies in Washington, told RFE/RL that the debate on the Iraq war strategy has been overly focused on troop levels. He said that U.S. troops' presence should be balanced with other factors, including the Iraqi government's efforts to reconcile the country's sectarian factions.
The two men’s testimony comes at a critical time for Bush administration. The president’s policy of adding more troops in hopes of giving Prime Minister Nuri al-Maliki’s government more time to make significant political strides is on trial with members of Congress -- who hold the purse strings when it comes to future war funding.
Antiwar Protesters Interrupt Hearing
Opinion polls show most Americans want to start bringing the troops home now. With the 2008 election little more than one year away, lawmakers are keenly aware of the need to reflect public sentiment if they want to hold onto their seats.
Indeed, even before Petraeus began to speak, antiwar protesters threatened to steal the show inside the Congressional hearing room.
In a scene reminiscent of the political hearings during the Vietnam War, antiwar hecklers interrupted Petraeus’s testimony several times and committee co-Chairman Ike Skelton had to repeatedly warn the audience against causing disruption.
Petraeus’s appearance before Congress was mandated by legislators last May, when they approved the last round of war funding. Lawmakers insisted that the money be tied to a status report three months on. Since Al-Qaeda attacked the United States on September 11, 2001, Congress has provided some $600 billion for the wars in Iraq and Afghanistan, with about 70 percent of that going to Iraq.
Today’s hearing was the first of three this week on the future of the war and comes in advance of Bush’s own address to the public, expected by September 14, on his future plans for U.S. engagement in Iraq.
As Petraeus and Crocker were testifying, the military reported that nine U.S. soldiers were killed and 11 injured in Iraq.
Read the full transcripts of RFE/RL's interviews with analysts Anthony Cordesman and Michael O'Hanlon on the U.S. strategy in Iraq.