The Pentagon on Thursday proposed trimming the number of Army troops by 13 percent as the debt-ridden United States winds down a decade of war but vowed renewed investment to exert power in Asia and the Middle East.

With pressure mounting to balance the US books, President Barack Obama's administration sought a nine percent cut in the 2013 budget compared with last year's request by retiring older ships and planes and pulling back two brigades from Europe.

Defense Secretary Leon Panetta, offering a budget request preview, said he was seeking to reduce the number of active US Army soldiers from 570,000 in 2010 to 490,000 by 2017. The Marines would be cut from 202,000 to 182,000.

Panetta proposed a $613 billion budget for the year starting in October -- a $525 billion base spending plan and $88.4 billion for combat operations, primarily in Afghanistan. The total request was $671 billion in the current year.

Panetta vowed to maintain US power in the Middle East and Asia -- where China's growing military has concerned the United States and its allies -- including by modernizing submarines and funding a next-generation bomber.

Panetta called for funding to station littoral combat ships in Singapore and patrol craft in Bahrain, part of the US strategy of forward-deploying its military to such small and strategically placed US allies.