A new flank in the "war on terror" has opened up in the central Asian state of Uzbekistan, where America's ally has launched a bloody crackdown against suspected Islamic militants.

At least 26 people were killed on Tuesday in the Uzbekistan capital, Tashkent, as police stormed a suspected rebel hideout. The hardline neo-Communist President, Islam Karimov, blamed Islamic extremists with foreign support for two days of attacks and explosions that left 19 dead. It is the worst outbreak of violence since an attempt to assassinate him in 1999. But there are fears that Karimov's repressive policies, with the tacit backing of Washington, may fuel the escalation of unrest.

The massive manhunt was launched after two female suicide bombers set off bombs on Monday at a children's store and a bus stop in the capital, killing three policemen and a child, in the first suicide bombings in a formerly Soviet central Asian republic.

On Sunday night, a blast at a suspected bomb-making hideout killed 10 people in the historic city of Bukhara.

"I call on everyone to unite and protect our country from enemies like this, to come forward against them as one fist," Mr Karimov, who has held power since before Uzbekistan's 1991 independence, said.

Mr Karimov has accused militants of the Hizb ut-Tahrir (Party of Liberation) of responsibility for the attacks. The banned radical group has never before been linked to terrorist acts and has denied responsibility.

Other suspects include militants of the Islamic Movement of Uzbekistan (IMU), based in the eastern Fergana valley which straddles the border with Kyrgyzstan. The IMU, which has been linked to both al Qaeda and the Taleban in Afghanistan, is bent on overthrowing the secular Government and was blamed for the failed bomb attack on President Karimov, which killed at least 16 people. Mr Karimov alleged that the attacks were planned six to eight months in advance, and said the planning and funding required for such attacks indicated that they had outside support.

Analysts and journalists with the Institute for War and Peace Reporting (IWPR) said American policy in Uzbekistan, where hundreds of US soldiers have been based as part of the response to the 11 September attacks, could be backfiring because of the perceived US support for President Karimov.

By allowing the military agenda to appear to be driving US relations with Uzbekistan rather than issues of democratisation and reform, critics say that the West has only encouraged Mr Karimov to continue to ride roughshod over human rights in his country. Islamic extremists "could play a critical role if disturbances, sparked by social and economic causes, escalate into violence," the IWPR said.

The President has arrested and tortured thousands of people in what the Government says is an attempt to crack down on terrorism. But Human Rights Watch yesterday accused the Government of waging a "merciless campaign" against Muslim dissidents.

One Uzbek accused of "religious extremism" died in prison in August 2002 after apparently being boiled to death.

Opposition parties are banned from taking part in elections, protest rallies are harshly put down and the media is tightly shackled. The population of 25 million lives in poverty and is kept cowed by the strongest police and security forces in the central Asian region.

The British Ambassador in Tashkent, Craig Murray, has been an outspoken critic of the Karimov Government, but his persistent protests earned him a Foreign Office investigation into his conduct.

For the Uzbek Government, the latest upsurge in violence could be "profitable" because it would enable the authorities to justify the crackdown on dissent in general.

Although responsibility for the latest violence in Uzbekistan remained unclear, the attacks have served the purposes of both the US and Russian Governments, anxious to highlight the hand of international terror.