MOSCOW, Jan. 11 (Xinhua) -- Former Soviet leader Mikhail Gorbachev said Monday that Russia and the United States should extend the New Strategic Arms Reduction Treaty (New START) and adjust their nuclear doctrines.

"During the election campaign, he (Joe Biden) said that the treaty should be extended. However, this, I believe, is only the first step," Gorbachev said in an interview with RIA Novosti news agency.

"It is necessary to agree on further reductions. It is important to negotiate and adjust their nuclear doctrines," he added.

Gorbachev said that Russia and the United States should shift to a no-first-use nuclear policy rather than the current one based on limitations.

In 2010, Washington and Moscow signed the New START, which stipulates limits to the numbers of deployed nuclear warheads and strategic delivery systems by both.

The New START, the last remaining nuclear arms control treaty in force between the two nuclear superpowers, will expire on Feb. 5.