MOSCOW (AP) — Russian and U.S. diplomats have traded mutual complaints over a landmark nuclear arms treaty, but pledged their adherence to it.

Thursday’s consultations in Moscow focused on the Intermediate-Range Nuclear Forces Treaty. The 1987 pact signed by President Ronald Reagan and Soviet leader Mikhail Gorbachev banned an entire class of nuclear missiles.

Amid the tensions over the Ukrainian crisis, the U.S. administration accused Russia in July of violating the pact. Moscow has rejected the claim.

The U.S. State Department said “both sides acknowledged the importance of the INF Treaty and reconfirmed their commitment to it,” but added that the meeting failed to assuage the U.S. concerns.

Russia’s Foreign Ministry said it hasn’t got satisfactory answers to its concerns, but emphasized that “the parties re-affirmed the importance of preserving the treaty.”

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