By Matthew Davis
BBC News, Washington
The United States has been put under increasing pressure over its policy on Uzbekistan after the hardline government's suppression of protests, in which hundreds are feared to have died.
Reports say several hundred people died when troops shot at protesters
The crisis has left the US walking a diplomatic tightrope.
Washington has been consistently critical of Uzbekistan's record on human rights but it has also relied on President Islam Karimov's help in its "war on terror".
The US has a large military base in Uzbekistan that is seen by the Pentagon as important for the projection of US power into the region.
It also has an eye on the Uzbek oil and gas reserves.
So while deeply concerned about the outbreak of violence, the United States has tried to avoid taking sides in public.
That position is becoming untenable, however.
On Monday, the state department gave its strongest condemnation yet of the violence, saying it was "deeply disturbed" by reports that unarmed demonstrators had been fired on, and calling for the Red Cross to be allowed into affected areas.
But spokesman Richard Boucher also condemned the violent protesters who had stormed government buildings, restating concerns over Islamic extremists.
Washington's policy in the past has been to privately cajole the Uzbek government over human rights abuses.
But the US has endured much criticism for failing to speak out against the regime.
In 2004, Washington gave $50.6m in financial assistance to Uzbekistan - some $10.7m of which was allocated to security and law enforcement.
Republican Congressman Dana Rohrabacher, the man charged by Capitol Hill to liaise with Mr Karimov, acknowledges that Uzbekistan has helped the US, but he is now urging a harder line.
"We should be getting tough with Mr Karimov in the same way that we try to get tough with people in the real world," he told the BBC.
"During the Second World War we had to deal with Joe Stalin. We had to, he was our ally against Adolf Hitler.
"Mr Karimov has been helping us in our efforts in Afghanistan, which were based on an attack on the United States of America which left 3,000 of our people dead.
"But maybe we should have been a little tougher."
Rachel Denber, deputy director for Human Rights Watch's Central Asia Division, said the US had "a schizophrenic policy".
"On the one hand you have the state department seeking to exert pressure on the Uzbek government and using all means to exert pressure," she told the BBC.
"And on the other hand you have the defence department willing to give the government a pass."
Washington has cut off some aid to the Uzbek government in response to its poor human rights record, and increased aid specifically for democratic reforms.
Some experts see the latest crisis as an opportunity, rather than a problem, for the US.
Chris Seiple, head of the Institute for Global Engagement, told the BBC: "This crisis can bring a new phase to our relationship.
"We can say to President Karimov, you have a choice: work with us and engage in reform, or we will not be there in the long term.
"The benefits of having our base in Uzbekistan is tactically important, but strategically insignificant."
However, for former US ambassador to Uzbekistan Joseph Pressel, the diplomatic high-wire act is more difficult because of the value of Uzbekistan to the US.
"There's a good deal of pressure on the United States. After all, human rights and the provision of human rights is a fundamental part of American foreign policy," he said.
"Any American government... has to balance the sets of issues that we have - the desire to secure human rights, and in the case of Uzbekistan produce political and economic reform as well - with the military co-operation that we have.
"It's very much a balancing act. In the case of a country like Uzbekistan, which really does matter to us, the balance is even harder."