It was approved unanimously by all 19 NATO ambassadors.
Under a plan approved by NATO ambassadors this week, the alliance's peacekeeping force will be reduced from 21,000 to 18,000.
A meeting of NATO ambassadors on Thursday in Brussels is expected to consider moving the military planning for air strikes to a final stage.
NATO ambassadors in Brussels scrapped a meeting planned for today as the talks here dragged on.
NATO ambassadors are now meeting nearly daily, and member nations have pledged fighter planes for air strikes.
NATO ambassadors will discuss the plan Wednesday in Brussels.
Carrying out the order either now or in the near future would require another vote of the 16 NATO ambassadors, diplomats said.
NATO ambassadors held their regular weekly meeting in Brussels on Wednesday, but the training issue did not come up, an alliance official said.
He was Serbia's NATO ambassador when he killed himself.
NATO ambassadors approved the basic concept of the force at a meeting in Brussels yesterday.