If it means that you have to take out half a dozen Taleban positions to 'rescue' your colleagues, then that's what you've got to do

In a news conference, the secretary of the country's security council, Mir Akbar Rakhman Mankulov, emphatically insisted that the US forces gathering here would not be allowed to launch offensive operations either by land or air from the Uzbek bases.

"It's not in Uzbekistan's interests to allow them to do more," he said.

But all the signs are that Uzbekistan is adopting a relatively broad definition of the terms "search and rescue" and "humanitarian".

Military analysts say that the highly trained US special forces typically carry out search and rescue missions, often using heavy firepower such as helicopters and strike aircraft to support their operations.

"If it means that you have to take out half a dozen Taleban positions to 'rescue' your colleagues, then that's what you've got to do," said one Uzbek analyst who declined to be named.

"Most people might sometimes find it hard to recognise the difference between a regular attack and search and rescue."

And equally, he said, it could be considered "humanitarian" to remove Taleban forces from a valley filled with civilians desperately in need of food and medical supplies.

Airbase sealed off

The evidence on the ground supports this.

Security and secrecy surrounding the US forces are extraordinarily tight.

President Karimov agreed to let US troops use Uzbek airbases

The government has repeatedly refused to name the base the Americans are using, though it is widely understood to be the Khanabad airbase just outside Karshi in southern Uzbekistan, close to the Afghan border.

A day before the US forces were due to arrive, local police sealed it off with roadblocks.

It is now impossible for ordinary civilians to move within 10 kilometres (six miles) of the base.

Local farmers have reported seeing a steady stream of heavy transport aircraft landing and taking off, while one resident who works on the base has reported seeing strike aircraft and helicopters.

Fundamentalist fear

The Uzbeks have good reason to support the US-led attack on the Taleban.

It is deeply concerned about the possibility of being drawn into the maelstrom of violence.

Uzbekistan fears the conflict will spread across its border with Afghanistan

Several years ago, the Taleban leadership in Kandahar spurned an overture from Tashkent to form a working relationship, and have since harboured and trained the radical militant Islamic Movement of Uzbekistan (IMU).

In the 1990s, the IMU launched a violent campaign to carve out an Islamic state from the Ferghana Valley in the north-east of Uzbekistan - a territory which spills over into neighbouring Tajikistan and Kyrgyzstan.

The IMU also declared a jihad, or holy war, on all three governments, and the Uzbek Government has accused it of responsibility for planting a series of car bombs in Tashkent in 1999.

Beyond that, the government is also worried that the Taleban may honour its pledge to lash out over the border should the US troops here be involved in military action.

The government's words have been designed to placate the Afghans, while they see the US presence as insurance against a wider war.

Political repression

Few analysts believe the Uzbek Government's co-operation has come without a price.

The President, Islam Karimov, said all they asked for was help in maintaining a stable and peaceful Uzbekistan.

Human rights groups fear an increase in political repression in Uzbekistan

But human rights observers, including Ruslan Sharipov of the Human Rights Society of Uzbekistan, has interpreted that as meaning the United States would turn a blind eye to crackdowns on opposition groups, and the IMU in particular.

"The situation was bad before, but it is now very dangerous for religious freedom and political opposition," he said.

"There are already some 10,000 political and religious prisoners in this country and there is great censorship. I am afraid that the US will take the pressure off Uzbekistan over human rights now, and that things could get a lot worse."

Financial aid

Economists also suspect that Uzbekistan has asked for favours to help boost the nearly stagnating economy.

The International Monetary Fund and Tashkent parted company in a dispute over the Uzbek Government's refusal to reform its financial sector - a condition for further IMF loans.

Uzbekistan has appealed for financial aid

Hugo Milderhaud, the Tashkent manager for the Dutch bank ABM Amro, believes there are two possible scenarios.

Either the US has agreed to pressure the IMF to resume its loans, along with some help to liberalise the financial sector; or Washington will push through a financial aid package that will include new World Bank loans, softer loan repayment conditions, and either the postponement of interest repayments or the waiver of debt.

"I personally think it will be the latter. The US is in no position to impose conditions on Uzbekistan because it badly needs the government's help. That would be good for the country in the short-term, but I'm not so sure about the long term," Milderhaud said.