WASHINGTON — U.S. aid for Iraq's army and police units will be needed for the foreseeable future, although the security forces are becoming increasingly independent, a senior general will tell Congress on Wednesday.

In written remarks prepared for a House Armed Services Committee hearing, Army Lt. Gen. James Dubik said that the size of Iraq's forces have grown by more than a quarter in the past year, from 444,000 to 566,000. They also are improving their ability to execute operations on their own.

But they still lack experienced military leaders and have yet to become proficient at training new recruits, added Dubik, who until last week led the Multi-National Security Transition Command in Iraq.

Dubik's testimony comes as the Iraq war remains a key issue in the upcoming presidential elections and progress of Iraq's security forces is widely seen as necessary to help smooth a U.S. exit to the unpopular five-year war.

"Our assistance may change in organization and size over the coming months or years, but some form of partnership and assistance, consistent with strategic objectives is still necessary," Dubik wrote. "The Iraqis know this; we should remember it too."

When he testified before Congress in January, Dubik said Baghdad was on track to reach some 580,000 members by the end of the year but that they were still a long way from becoming self-sufficient. Iraqi officials estimated to him that the country probably won't be able to assume responsibility for internal security until sometime between 2009 and 2012 or defend its borders before 2018, Dubik said.

In this week's testimony, Dubik recommends streamlining complex laws and regulations that he says have delayed U.S. military equipment purchased by Iraq. Iraq has ordered $2.7 billion in equipment, but received just $1.4 billion.

Army Lt. Gen. Frank Helmick assumed control of the U.S. training command last week. Dubik is retiring after 37 years of service.