The U.S. may be able to reduce combat forces in Iraq by next spring, if Iraq's own security forces continue to grow and improve, a senior American commander said Friday.

Lt. Gen. Raymond Odierno, the top day-to-day commander of U.S. forces in Iraq, did not predict any U.S. reductions but said it may be feasible by spring. There are currently 156,000 U.S. troops in Iraq.

Speaking to reporters at the Pentagon from his headquarters outside Baghdad, Odierno gave an update on the series of U.S. offensives that are underway in Diyala province northeast of Baghdad and in areas south and west of the capital. He said U.S. and Iraqi troops have made important progress.

"I think if everything goes the way it's going now, there's a potential that by the spring we will be able to reduce forces, and Iraq security forces could take over," he said. "It could happen sooner than that. I don't know."

He also cautioned that, because the insurgents in Iraq have proven so resilient and adaptive, making any prediction is risky.

"There's so many things that could happen between now and then," he said, referring to next spring.

He also said it's too early to say how long the recent addition of almost 30,000 U.S. troops should be maintained. The overall U.S. commander in Iraq, Gen. David Petraeus, is due to report to Washington in September on what the troop buildup is accomplishing, and he has said he intends also to recommend a way forward.