The US Secretary of State, Mr Colin Powell, yesterday said Russian officials have hinted they may be willing to allow more testing of a proposed US missile shield. Washington believes the shield is possible under the 1972 anti-ballistic missile (ABM) treaty.
A flexible Russian approach could delay US plans to unilaterally withdraw from the treaty if Washington and Moscow are unable to come up with a compromise replacement that would allow deployment of a national missile defence system.
"I have had discussions with Russian colleagues of mine who suggest we can probably do more testing than we think we can under the treaty," Mr Powell said on his way back to Washington from Shanghai.
"We're looking at all of that," he said, but stressed that President Bush would not allow the ABM treaty to "constrain" his plans for a missile shield that would be prohibited by the current accord.
Mr Bush, who met President Putin in Shanghai, has vowed to continue testing missile shield technology and warned that at some point soon those tests will violate the ABM pact, which Moscow believes is the cornerstone of its strategic relationship with Washington.
Mr Bush has also said he will not violate the treaty. He must notify Moscow that Washington intends to withdraw from the pact six months before the tests.
The first US test that could violate the treaty is tentatively set for the second quarter of next year.
The treaty between the US and the former Soviet Union prohibits the parties from developing any wide-scale missile defence system. It had long been regarded as the key to the Cold War concept of deterrence based on the notion of mutually assured destruction.
However, with the Cold War over and the Soviet Union gone, Mr Bush and his top aides believe ABM to be a hindrance to building defences against possible missile attacks from so-called "rogue states" like North Korea and Iraq, which are not bound by the treaty.
"We must truly and finally move beyond the Cold War" and defend against "new threats", Mr Bush said on Sunday at a joint news conference with Mr Putin.
Mr Putin said they had "made some progress" towards resolving the dispute over the ABM treaty, but called the pact "an important element of stability in the world". At the same time Mr Putin acknowledged the need to face possible future threats, and said Moscow is "prepared to discuss that". Mr Powell did not say whether Mr Putin's talks of progress related to his conversations with Russian officials about flexibility in the treaty.