KUKES, Albania (AP) _ NATO commander Gen. Wesley Clark, visiting U.S. soldiers readying an Apache helicopter unit for action in Kosovo, says the air campaign against Yugoslavia is ``right on schedule.''

``We said it would be a serious and sustained effort,'' Clark said Sunday. ``We said it would progressively intensify. We've more than doubled the aircraft that are engaged. We're bringing in additional reconnaissance means and I think we're having effect.''

The general came to northern Albania, near the Kosovo border, to check on the progress of Task Force Hawk, which features U.S. Army Apaches known for their tank-killing abilities.

``I don't have a specific date as of when the Apaches will be operational, but we're on track and they won't be too long,'' he told reporters.

The deployment of the Apaches is expected to herald a new phase in NATO's air war against Serb forces in Kosovo. They are heavily armed and, with their low-flying ability, are considered to be highly effective weapons against ground targets such as Serb troops.