WASHINGTON (AP)- Gen. David Petraeus, the top U.S. commander in Iraq, said Thursday that conditions in Iraq may get harder before they get easier and will require "an enormous commitment" over time by the United States.
Speaking as the Senate debated veto-threatened legislation to start bringing home U.S. forces in October, Petraeus called the war there "the most complex and challenging I have ever seen."
The four-star general, named by President Bush to oversee the recent buildup of American forces, cited some progress in the two months since the troop increase began. Still, he said, "there is vastly more work to be done across the board. ... We are just getting started with the new effort."
He avoided commenting directly on the legislation before the Senate, which passed the House Wednesday night. "I have tried to stay clear of the political minefields of various legislative proposals," he said.
But his comments made it clear that his war plan did not include a significant reduction of U.S. forces anytime soon.
"This effort may get harder before it gets easier," Petraeus told reporters at a Pentagon briefing, depicting the situation as "exceedingly complex and very tough."
He said that the increasing use of roadside bombs and suicide attacks, plus the greater concentration of U.S. troops among the population, has "led to greater U.S. losses" as well as increased Iraqi military casualties.
Asked how many troops he thought would have to remain in Iraq - and for how long - to finish the job, Petraeus said, "I wouldn't try to truly anticipate what level might be some years down the road." However, he noted historical precedents to long U.S. peacekeeping missions.
"It is an endeavor that clearly is going to require enormous commitment and commitment over time, but beyond that time I don't want to get into try to postulate how many brigades or when we would start to do something," he said.
Petraeus said matters were made worse by "exceedingly unhelpful activities by Iran and Syria, especially those by Iran."
Asked whether senior officials in the Iranian government were sanctioning sending weapons and technology to insurgents in Iraq, the U.S. general said it was hard to say. "We do not have a direct link of Iranian involvement," in attacks, he said.
Petraeus also said that, while the fledgling Iraqi government is often billed as a unity government among Shiites, Sunnis and Kurds, it actually is not.
"It is not a government of national unity. Rather, it is one comprised of political leaders from different parties that often default to narrow agendas and a zero-sum approach to legislation," the general said.
He said that was one reason why progress has been so slow on deciding how to divide up oil revenues and pass budget and emergency powers laws.
Despite the disappointing pace, Petraeus said he believes that Iraqi Prime Minister Nouri al-Maliki and other leaders "are committed to achieving more in this area in the months ahead."
Petraeus cited slowly improving conditions in turbulent Anbar province in western Iraq, noting it had been "assessed as lost six months ago."
He said the increased U.S. presence in various outposts has enabled Iraqis "to stitch together the fabric of society that was so torn."
But he said improvements, such as the reopening of shops and the return by some residents to their homes, are "often eclipsed by sensational attacks that overshadow our daily accomplishments."
"Iraq is in fact the central front of al-Qaida's global campaign," he said. "Al-Qaida-Iraq remains a formidable foe with considerable resilience and a capability to produce horrific attacks."
"This group's activities must be significantly disrupted at the least for the new Iraq to succeed," he added. "The key to success is disrupting their attacks."