Russia is talking to the US about agreeing the details a treaty that placed limits on deployed nuclear weapons and missile launchers, its Foreign Ministry has said.

Russian Deputy Foreign Minister Sergey Ryabkov met his US counterpart Thomas Shannon in the Finnish capital Helsinki on Tuesday night to discuss implementing a provision of the 2010 Strategic Arms Reduction Treaty (New START) by the February 2018 deadline.

The treaty obliges the two biggest nuclear powers to limit the number of deployed warheads to 1,550 each, and 700 deployed missiles and bombers, by February.

Mr Ryabkov said Moscow and Washington “agreed that there could be no deviation from requirements of the agreement.”

He said a meeting of the Russian-US commission on implementing the treaty would take place “in the near future.”

Meanwhile US Defence Secretary James Mattis’s visit to the US’s biggest nuclear weapons base yesterday, where he pledged to keep all parts of the nuclear “triad” — ground, submarine and air-launched nukes.

Ex-president Barack Obama kicked off a $1 trillion nuclear “modernisation” programme, due to last 30 years, in 2016.

And last month the Pentagon signed contracts for new-generation intercontinental ballistic missiles and air-launched cruise missiles, and is developing a new first-strike stealth bomber.