MOSCOW - Russia's attitude of "denial" over concerns about biological weapons makes it more difficult to secure U.S. funds to destroy its massive chemical arsenal, which has been decreased by just one percent since Moscow vowed to get rid of it, a U.S. Senator at the forefront of efforts to reduce the threat from Russian mass destruction weapons said Friday.

Of the 40,000 metric tons (44,000 tons) of chemical weapons Russia says it possesses, just 400 metric tons (440 tons) have been destroyed, said Sen. Richard Lugar, an Indiana Republican and an initiator in 1991 of the Nunn-Lugar program to help the Soviet Union an its successor states destroy and safeguard weapons of mass destruction.

The focus in efforts to destroy chemical weapons is a facility in the Ural Mountains city of Shchuchye, which Lugar said is one of seven sites in Russia where they are stored.

Lugar said the facility, under construction since March, should be completed in mid-2005 if there are no delays. He said Russian officials told him that the chemical weapons stored at Shchuchye, which are mostly shells containing nerve gas, would not be fully neutralized before 2012 - the current target date for the destruction of Russia's entire chemical arsenal.

At a summit in June 2002, Russia's partners in the Group of Eight pledged up to US$20 billion over 10 years to help Russia dispose of its nuclear, biological and chemical arsenals. Lugar, chairman of the Senate Foreign Relations Committee, said it appears likely the planned US$1 billion for the coming year will be included in the U.S. budget.

But he said evasive behavior by Russian officials authorities over questions about biological weapons gives members of the U.S. Congress a reason to seek to block funds. While Russia has made clear declarations about its chemical and nuclear stockpiles, he said, "still there is a sense of denial" surrounding biological programs.

"The denials with regard to the biological situation offer an avenue where opponents of spending Nunn-Lugar money can say 'See, still, we really don't know exactly,"' he said.

The United States believes that Russia had four military biological facilities in the Soviet era, Lugar said. "Now conceivably, the general who visited with me yesterday may be correct that at all four of these there's not a single weapon at this moment. There may be pathogens in an icebox, we don't know what there is. The fact is, we don't know," he said.

He cited problems he encountered on a visit last year, when a trip to one of the facilities was delayed when he was told his plane would not be allowed to land there. Eventually the flight was given clearance, but Lugar said he did not see the military personnel at the facility.

Despite the difficulties, Lugar said it is counterproductive for U.S. lawmakers to demand full Russian compliance with all its commitments on weapons of mass destruction before allowing funding. "It is not useful to set up conditions in which there has to be 100 percent compliance before we do anything," he said.

U.S. aid for construction of the Shchuchye facility was halted last year after Russia failed to meet commitments for aid established by Congress, but was resumed early this year after Congress allowed President George W. Bush to waive the requirements.

The U.S. administration wants Congress to grant the president the permanent authority to annually waive Russian compliance requirements both for assistance for the Shchuchye facility and broader aid under the Nunn-Lugar program.