"As for reaching an agreement by 2026, it is impossible to make predictions here, because the dynamics of international relations, the military-political situation in the world is changing very quickly. And it's hard to speculate about this," Belousov told journalists at the Review Conference of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).
He added that there is still enough time to reach a new agreement, but this requires political will and real intent.
US President Joe Biden said on Monday, ahead of the NPT conference, that his administration was ready to promptly negotiate a new arms control framework to replace the New START treaty with Russia when it expires in 2026, provided that Moscow demonstrates readiness to resume work on nuclear arms control with the United States.
Belousov stressed that Moscow will not accept any preconditions from Washington.
Signed in 2010, the New START is a nuclear arms reduction treaty between Russia and the US, which aims at halving the number of strategic nuclear missile launchers. It was set to expire last year, however, Moscow and Washington agreed to prolong the treaty for five more years without renegotiating any of its terms.