Russia is still waiting for the United States to respond to President Vladimir Putin’s proposal to informally extend for a year the provisions of the last remaining nuclear arms pact between the two countries, the Kremlin said on Thursday.

Kremlin spokesman Dmitry Peskov told reporters that the expiry of the New START treaty on February 5 could lead to a serious gap in the legal framework regulating nuclear arms.

New START, which was signed by Presidents Barack Obama and Dmitry Medvedev in 2010, sets limits on the strategic weapons that each side would use to target the other’s critical political and military centres in the event of a nuclear war.

It caps the number of deployed strategic warheads at 1,550 on each side, with no more than 700 deployed ground- or submarine-launched missiles and bomber planes to deliver them.