US, British and French ground troops finally arrived in Afghanistan yesterday, but unlike other recent missions, they came not to keep the peace but to make war.
Washington said that its special forces, which so far have been restricted to co-ordinating air strikes, are now fighting alongside rebel troops in battles around the Taliban city of Kandahar.
Meanwhile British and French troops landed at two key air bases - the British arriving at Bagram, north of Kabul, and the French at Mazar-e-Sharif, recently captured from the Taliban by the Northern Alliance.
Officially, these two deployments are to facilitate the movement of humanitarian aid. But in reality, most aid continues to move by road.
And the secrecy surrounding the British move suggests something else is intended.
Bagram was ringed by tight security yesterday hours after the British arrived in five transport planes. The British troops themselves were kept out of sight for most of the day.
Managing to sneak past the guards, I spotted a team of special forces soldiers, wearing jeans and casual clothes, gathered outside a house with a large green satellite dish behind it. A green dune buggy was parked outside - it would not have looked out of place on a beach.
The soldiers ignored my calls and an Afghan sentry was soon chasing me out of the base.
US special forces around Bagram have worn casual wear for some weeks, hoping to look less conspicuous to visiting journalists.
At the gate I got a final taste of their security. Another special forces man drove a pick-up truck through the main gate without stopping.
The gate guard fired twice in the air to bring the man to a halt, after which there was a brief argument ending in the threat that even special forces soldiers must first identify themselves at Bagram.
Many think the arrival of these troops, and of French marines in Mazar, has to do with a second phase of this war. The first phase was the air support for the Northern Alliance forces, enabling them to break through Taliban defences in the north of the country and capture the capital, Kabul.
But in recent days the battles against the Taliban have become more difficult. The fighting is now in ethnic Pashtun areas, with the predominantly Pashtun Taliban fighting against its fellow tribesmen.
The tanks and guns of the Northern Alliance are operated by minorities, the Hazaris, Shias, Tajiks and Uzbeks, and play no part in the new fighting.
Although the Pashtuns have scored a notable success - the conquest of the city of Jalalabad near Pakistan - they are struggling around Kandahar.
Meanwhile, in the north Taliban forces led by Arab and Pakistani volunteers - soldiers who face execution if caught by the Alliance - have counter-attacked from their stronghold of Kunduz. With this in mind, Western troops are now on the ground ready to provide added fire power.
US warplanes bombed Taliban positions around Kandahar and Kunduz, despite calls from Pakistan for restraint during Islam's holy month of Ramadan which began on Thursday night.
On Friday, the US Defence Secretary, Mr Donald Rumsfeld, said US special forces have been involved in ground combat, killing Taliban soldiers. No Americans have died in the operations.
Mr Rumsfeld also said several Taliban leaders had been captured by opposition Afghan forces and that US officials now in Afghanistan were planning to interrogate them.