Jaap de Hoop Scheffer says Nato is not abandoning Kosovo
Nato defence ministers have agreed to reduce the numbers of peacekeeping troops in Kosovo.
The alliance is to cut its operation from around 14,000 troops now to 10,000 over the coming months, officials said.
Numbers could fall to about 2,500 personnel over two years if the right security conditions are in place.
The move follows a Nato review which concluded that the situation in Kosovo was sufficiently safe after it declared independence from Serbia last year.
The force, known as Kfor, has been in Kosovo for 10 years.
It was deployed following a Nato air campaign against Serbia to stop a crackdown on separatist ethnic Albanians.
Alliance Secretary General Jaap de Hoop Scheffer said the reduction would happen in a "phased manner, and each step will be decided by the North Atlantic Council (of Nato nations) based on military advice".
He said the alliance had yet to set a firm date for the cut, but added: "That date might well be January 1" 2010.
Correspondents say that as tensions in Kosovo have eased, the alliance is under pressure to re-deploy troops to places like Afghanistan.
But Mr Scheffer stressed they are not abandoning Kosovo.
"Kfor will remain in Kosovo, it will remain responsible for a safe and secure environment," he told reporters after chairing the meeting.
A vocal minority of ethnic Serbs - backed by Moscow and Belgrade - continues to oppose Kosovo's independence.
But the fledgling state, made up mainly of ethnic Albanians, has strong backing from the US, and its independent status has been recognised by most EU countries.