Washington: The US is weighing the option of reducing the number of US combat troops stationed in Europe as part of a new military strategy unveiled last week, a senior defense official has said.

No official decision has been taken on the issue and the final outcome depends on the next defense budget due to be released on February 6, said Julianne Smith, principal director for European and NATO policy.

"There are four brigade combat teams (BCTs) based in Europe but a significant portion of those has been deployed elsewhere," Smith said.

"More or less for the last 10 years, we've had two of the BCTs in Afghanistan. So the question is where do they return to," she said.

Defense officials have for years debated how many troops to keep in Europe and former president George W Bush's administration had planned to reduce the number of combat forces from four brigades to two.

Each Army combat brigade team has about 3,500 troops.

The US military has nearly 81,000 service members in Europe, including 43,000 Army personnel and 31,000 from the Air Force, according to Pentagon estimates in September last year.

Defense officials have said at least one brigade likely will be eliminated in Europe.

President Barack Obama last week presented a revised military strategy designed to shape future defense spending amid fiscal pressures. The strategy called for increasing the

US military's presence in Asia while signalling a likely reduction in American forces in Europe.