The United States and its key allies expressed grave concerns on Friday about the growing cooperation between North Korea and Russia and urged an end to North Korean arms transfers used against Ukraine.

The U.S. Secretary of State and foreign ministers from Australia, Canada, France, Germany, Italy, Japan, New Zealand, South Korea, and the United Kingdom, along with the EU High Representative, issued a joint statement highlighting their recent coordination of sanctions measures in response to such activities.

“Our governments firmly oppose these ongoing arms transfers, which Russia has employed to attack Ukraine’s critical infrastructure, prolonging the suffering of the Ukrainian people,” they stated.

The statement, referring to North Korea by the initials of its official name, expressed deep concern about the “deepening DPRK-Russia cooperation” in “blatant violation” of multiple U.N. Security Council resolutions.

Moscow and Pyongyang have denied accusations of arms transfers but pledged last year to strengthen military ties.

Friday’s joint statement condemned Russia’s March veto of a U.N. resolution that would have extended the mandate of an expert panel responsible for monitoring the implementation of U.N. sanctions against North Korea.

“We urge the DPRK and Russia to cease unlawful arms transfers,” the statement said.

Days before its mandate expired, the issued a report confirming that a North Korean-made ballistic missile known as Hwasong-11 had struck the Ukrainian city of Kharkiv, violating U.N. sanctions.

Since Russia’s veto, the U.S. and its allies have explored alternative methods to coordinate and monitor sanctions on North Korea. South Korea, Japan, Britain, and others have taken action in response to the alleged arms transfers to Russia.

A U.S. State Department spokesperson described it as “the most extensive multilateral coordinated DPRK sanctions action to date.”

“We strongly urge both nations to immediately cease their malicious activities,” the spokesperson said.

The joint statement urged North Korea to take tangible steps toward abandoning its nuclear weapons and ballistic missile programs and to resume diplomatic efforts.