United States says Russian President Vladimir Putin launched exercises by strategic nuclear missile forces on Saturday.

Addressing a news conference on a visit to Lithuania, US Defence Secretary Lloyd Austin said Russian forces are beginning to uncoil and move closer to the border with its former Soviet neighbour.

Earlier, talking to reporters in Washington, U.S. President Joe Biden said United States believes Russian President Vladimir Putin has decided to invade Ukraine.

He said Russian troops currently have surrounded Ukraine and that the Washington believes Moscow would target Ukraine’s capital, Kyiv.