North Korea is under U.N. sanctions that ban trading in missile or nuclear technology that have driven its already dire economy deeper in trouble by cutting off what was once a lucrative source of hard cash.

Russia has often balanced criticism of the nuclear activities and missile launches of North Korea, a Soviet-era client state, with calls on other powers to refrain from belligerent actions against it, which Moscow says can be counterproductive.

Russia is a permanent member of the U.N. Security Council and is upset by any defiance of council resolutions. Past launches by Pyongyang have caused concern among Russians living near the country’s border with North Korea.