Washington’s concerns that Russia violated a 1987 arms control treaty “were not assuaged” during a meeting between the two sides in Moscow, the State Department said Thursday.

US negotiators nevertheless felt they had a “useful exchange of views” with their Russian counterparts and have “agreed to continue the dialogue,” it said in a statement.

Both sides “acknowledged the importance” of the treaty “and reconfirmed their commitment to it” during Thursday’s meeting, it added.

The US and Russia have accused each other of violating the bilateral Intermediate-Range Nuclear Forces Treaty, which first took effect on June 1, 1988, and was broadened after the Soviet Union broke apart.

Washington has raised concerns over Moscow’s development since 2008 of a new missile banned under the accord. Russia, meanwhile, wants the United States to abandon or limit its anti-missile shield plans in Europe, saying the project threatens its security.

The treaty required the destruction of all ballistic and cruise missiles with ranges of between 500 and 5,500 kilometers, as well as launchers and support equipment, by June 1, 1991, according to the State Department.