The move is one of several steps taken by the alliance in recent days to ensure it can deal with tensions, particularly in the Serb-dominated north of Kosovo.
"Two reserve battalions are now on a 'shorter notice to move'," said the source, using the military term for putting reserve troops on a higher state of readiness.
The source said the decision affected one British and one joint Austrian-German reserve battalion, both currently stationed outside the country.
"A number of companies have also been moved into the north from elsewhere in Kosovo," the source said of changes in the focus of the 16,000-plus NATO-led KFOR security force.
A NATO spokesman declined to comment on KFOR operational details but reiterated that the alliance had stepped up its presence in the north after violence there in the past week.
"The situation is obviously tense and volatile but remains relatively calm," spokesman James Appathurai said.
Güncelleme Tarihi: 28 Şubat 2008, 12:21