Washington believes that Moscow has violated the Intermediate-Range Nuclear Forces (INF) treaty, U.S. Secretary Defense James Mattis said on Thursday.

“We have a firm belief now over several years that the Russians have violated the INF and our effort is to bring Russia back into compliance,” Mattis said at a news conference during a NATO defense ministers' meeting in Brussels, Axar.az reports citing AA.

According to the U.S. Department of State website, the treaty was signed in 1987 between the U.S. and the then-Soviet Union.

The treaty requires parties to destroy their ground-launched ballistic and cruise missiles with ranges of between 500 and 5,500 kilometers, their launchers and associated support structures and support equipment within three years after the treaty enters into force.

Moscow repeatedly affirmed its commitment to implement the treaty.

"We spoke about our willingness to discuss the concerns of both parties, ours and the Americans’. Unfortunately, Washington persistently continues to make allegations against us, while refusing to specify them," Russian Foreign Minister Sergey Lavrov said in October.