Germany ? The Pentagon plans to extend its buildup of several thousand combat troops in Afghanistan, initially announced as lasting until late spring, well into next year, a senior U.S. military official said Friday.

The move comes as U.S. and allied commanders anticipate a renewed offensive this spring by the Taliban, and as they seek additional reinforcements from NATO countries. The effort to bolster forces there so far has brought only limited success, with a few nations promising handfuls of additional troops and equipment.

The extension of the U.S. buildup means American troop levels in Afghanistan, which increased this month to about 26,000 – the highest of the war – will remain roughly the same until at least spring 2008. Until now, a level of 22,000 to 23,000 had prevailed through much of last year.

The decision, expected to be announced in Washington as early as next week, entails sending an Army combat brigade to replace the 3rd Brigade of the 10th Mountain Division when it leaves this spring.