Rear Admiral Thomas Wilson, Pentagon director of intelligence, listed "microwaves" in the command and control targets which have been hit, saying civilian microwave towers had military uses.
This confirmed a view, around since the F-117 stealth fighter was shot down, that mobile phones are an integral part of the Yugoslav military communications - and they pose a major problem.
Buildings and other fixed sites associated with the integrated air defence system can be easily targeted, but hundreds or thousands of soldiers with mobile phones are more difficult to silence. Unless this is done, the Apache helicopters and other aircraft on low-level attacks will be in trouble.
"We are fighting a mobile phone war," said Wing Commander Andrew Brookes, air analyst at the International Institute for Strategic Studies. "All you need is someone at the end of an allied runway with a mobile phone, and they can tell when aircraft are taking off and when you might expect them.
"If you have guys at the other end with SAM-7 portable anti-aircraft missiles then the Apaches are going to get an unfortunate reception." He said that during the Second World War, Italian fascist spies phoned enemy commanders to warn them when Allied bombers took off from bases in occupied Italy.
The problem is that Nato is fighting a limited, high-tech conflict against a dispersed and relatively low-tech enemy. Nato training and development of weapons systems were designed for a different war - against the highly centralised forces of the former Eastern bloc.
Since Tito's days, Yugoslav tactics have been to defend in depth, surrendering ground to a superior enemy to harry them in small-scale or guerrilla actions. Units would operate semi-autonomously, living off cached stores of food and ammunition to protect their command network.
Now Nato is hitting the fixed targets they know throughout Yugoslavia, but making little impact on the forces in Kosovo. Pentagon estimates show only 10 to 15 per cent of the mobile SAM-6 missile systems are destroyed, leaving about 45 in place to face low-flying aircraft.
"We have been buying and preparing for a premier league fixture, but we are not fighting that," said Wing Commander Brookes. "What we now have is a Vauxhall Conference game on a vertical hill in Holmfirth where it's snowing. It's not what we're supposed to be doing, and there will be a lot of re-assessing going on when this is finished."Reuse content