US Secretary of Defense Ashton Carter will participate in a session of NATO’s Nuclear Planning Group (NPG) in Brussels, Belgium, which will focus on adjusting the alliance’s nuclear posture, US Department of Defense said in a Twitter message on Tuesday.

The United States has accused Russia of violating the 1987 Intermediate-range Nuclear Forces (INF) Treaty, which prohibits the development, testing, or fielding of ground-based cruise missiles with a range of 300 to 3,400 miles.

Russia has rejected the accusations, and claimed that Washington’s Europe-based missile defense system violates the INF treaty.

“The NPG will focus on adjustments to NATO’s nuclear deterrence posture in light of Russia’s nuclear strategy,” the Defense Department stated.