With clearer skies over Kosovo Nato is at last bringing its full fire-power to bear.

Constrained by poor visibility for most of the first ten days of this air campaign, the Alliance was largely forced to rely upon nightly cruise missile attacks against fixed Yugoslav targets.

This was a war of attrition waged in a minor key. But now Nato has upped the tempo.

Significant damage: Barracks in Kragujevac, Serbia

It claims some successes against Yugoslav troops and special police units on the ground in Kosovo. And its strategic air offensive has started to do real damage to Yugoslavia's military infrastructure.

Bridges, petrol depots, key military industries, as well as headquarters buildings in Belgrade have all been hit. Belgrade television reports tend to back up the daily claims shown on the video clips at the briefings in London, Brussels and Washington.

Cumulative impact may be taking its toll

Over time, the effects of Nato's action will undoubtedly constrain the Yugoslav forces ability to operate. But it is going to be a long haul and additional Nato reinforcements may well be needed.

The weather too may change in Belgrade's favour, once again slowing down the impact of the Alliance campaign.

Risks remain considerable

Nato still insists that it is not at war. It is undoubtedly trying to reduce civilian casualties to a minimum.

Air strikes might not be enough

But casualties there are. And lines of communication for the military are also key civilian transport routes.

This is increasingly looking like a war - albeit of a limited sort . And if the Nato offensive is ultimately successful and Yugoslav forces in Kosovo do begin to withdraw, then Alliance ground troops may well have to go in to fill the vacuum.

End-game changing

But there are also signs that the parameters of the end-game are changing.

Initially Nato's demand was that Mr Milosevic should sign the Rambouillet peace plan and grant Kosovo a three-year period of autonomy, after which its long-term future would be decided.

Ethnic cleansing may have killed Rambouillet accord

But the peace plan - accepted by the Kosovar Albanians - maintained Yugoslav sovereignty over Kosovo. There have been a number of hints from western leaders that the ethnic cleansing has changed the terms of the debate.

American spokesmen have insisted that what is now required is a full withdrawl of Yugoslav army and special police units from Kosovo. President Clinton has indicated that Mr Milosovic, by his actions, may have forfeited Serbia's claim to Kosovo and Nato Secretary-General Javier Solana has expressed his personal opinion that it will be very difficult to deal with the Serbian leader in the future.

'Digging in for the long-haul'

Already in the corridors at Nato an idea of one possible end-game is emerging.

According to this view Mr Milosevic would be forced to evacuate his forces from Kosovo. Some form of interim political arrangements would need to be put in place. And Nato troops would move swiftly into the vacuum to provide security and help rebuild Kosovo's shattered infrastructure.

This is not yet official Nato thinking. But there are clear signals that the Alliance believes that any settlement must go beyond the Rambouillet accord and that in the wake of the Yugoslav forces' sweep through Kosovo the ethnic Albanians can hardly be expected to accept the sovereignty of a man described by Nato as the "butcher of Belgrade".

Diplomatic insiders say that political cohesion in the Nato alliance is growing.