Russia's strong support for the U.S.-led war against terrorism has led to a remarkable improvement in relations between Moscow and Washington in recent months. But now there are signs of strain between the United States and Russia over various issues.

The war in Chechnya, arms control, threats to press freedom - these are just some of the issues which have resurfaced in public over the past week.

After months of little comment on the conflict in Chechnya, the U.S. State Department said last week that Russia uses "overwhelming force" in its war against rebel fighters there.

Department spokesman Richard Boucher said Russian operations there indicate a "continuation of human rights violations and the use of force against civilian targets."

For its part, the Russian Foreign Ministry on Friday sharply criticized a U.S. decision that effectively bars Russia from importing American high-speed computers.

In a statement, the ministry said Washington is discriminating against Russia in a policy that allows many other countries to obtain such new computers.

The United States has also expressed concern about a Moscow court ruling Friday to close down the only television channel that remains free of Kremlin control in a move seen as political. Analysts say these issues are an indication the relationship between the U.S. and Russia remains complex, despite the new-found cooperation in the war against terrorism.

Russia, for example, has long maintained that the rebels in Chechnya are international terrorists, and there have been foreign mercenaries fighting alongside the Chechens.

But the U.S., as well as European countries, says this doesn't justify the heavy-handed tactics used by Russian troops in the breakaway region.

Washington has also criticized Russia for helping build a nuclear power plant in Iran despite Russian insistence this will not help Tehran acquire sensitive nuclear technology.

Most of these issues receded into the background after the attacks of September 11, and President Vladimir Putin took a strong stand in support of the war against terrorism.

He stood firm even when Russian military leaders were upset at seeing U.S. troops arrive in the former Soviet states of central Asia, such as Uzbekistan.

The two countries could be at odds in the next phase in the war, especially if there is any attack on Iraq, a long-time ally of Russia's.