Britain plans to substantially scale back its troop numbers in Iraqi during 2009, the head of the country's armed forces said Sunday.

Air Chief Marshal Jock Stirrup said the U.K. will withdraw soldiers to help ease major strains on Britain's military, which has been stretched by deployments in both Afghanistan and southern Iraq.

Britain had planned to cut its number of troops in Iraq from 4,000 to 2,500 earlier this year, but postponed the withdrawal in March amid a spike in militia violence.

"I would expect us to see further substantial progress towards a more sustainable tempo in the course of the next year," Stirrup told British Broadcasting Corp. television, referring to lowering troop numbers in Iraq.

Britain has increased to almost 8,000 its number of troops in Afghanistan and Stirrup said the U.K. military does not have the capacity to keep soldiers deployed across both fronts for much longer.

The U.K. troops in Iraq are based at an airport camp on the fringe of the oil-rich southern city of Basra and no longer have an active combat role. Soldiers are involved mainly in training Iraqi soldiers, police and border guards.

Prime Minister Gordon Brown is scheduled to make a statement to lawmakers on future plans in Iraq within the next two weeks, but his office has insisted he will not set out any timetable for the withdrawal of British forces.

Stirrup said the spike in violence and complications in training Iraqi soldiers had caused delays to earlier planned withdrawals, but said soldiers will be pulled out of Iraq next year.

Britain's Sunday Times newspaper reported Sunday that the U.K. plans to withdraw the majority of British troops from Iraq by the middle of 2009, citing unnamed defense sources.

Stirrup, the overall head of Britain's military, said he believed troops are likely to remain in Afghanistan for several years. He also claimed the country will need assistance from the rest of the world for decades.

"The international community, I think, if the enterprise is to be successful, will need to be engaged for decades," Stirrup told the BBC. "What I am talking about is across the full spectrum of effect, in terms of reconstruction, governance, finance and the economy."