US Secretary of State Antony Blinken met with France's Catherine Colonna, German Foreign Minister Annalena Baerbock and UK counterpart James Cleverly on the sidelines of the Munich Security Conference, a statement said.

They "discussed their concerns about the deepening two-way military cooperation between Iran and Russia, and its implications for the security and stability of the region and beyond," a statement by Blinken's spokesman said.

"They underscored their concern about Iran's nuclear escalation and its lack of cooperation with the International Atomic Energy Agency, calling on Iran to reverse course."

Negotiations on Tehran's contested nuclear policy with the West aimed at reviving a landmark deal have been in the doldrums for several months.

Russia's invasion of Ukraine is on top of the agenda at the Munich conference, being attended by world leaders.