Russia and North Korea on Tuesday advocated closer collaboration including in the defense sector, the latest show of deepening ties between the countries at odds with the United States.

Moscow and Pyongyang — both increasingly isolated from the West and weighted with sanctions — have drawn closer since the Kremlin deployed troops to Ukraine and commenced large-scale hostilities last year.

North Korean leader Kim Jong Un “stressed the need to further develop tactical and strategic cooperation and interaction between the two countries in the fields of defense and security,” the country’s defense minister said in a statement carried by the state-run RIA Novosti agency.

Russian President Vladimir Putin earlier Tuesday called for deeper ties, in a congratulatory message to Kim marking his country’s National Liberation Day.

“I am sure that we will continue to build up bilateral cooperation in all areas for the benefit of our peoples, in the interests of strengthening stability and security on the Korean Peninsula and in the Northeast Asian region as a whole,” Putin said in a statement distributed by the Kremlin. 

Putin said it was during Korea’s liberation from Japan and “harsh wartime” that groundwork was laid for close cooperation between Moscow and Pyongyang.

The leaders’ statements came after Defense Minister Sergei Shoigu last month hailed Russia’s partnership with North Korea during a meeting with his counterpart Kang Sun Nam in Pyongyang.

Secretary of State Antony Blinken responded to the visit saying the United States believed Shoigu was in North Korea to secure supplies of weapons to aid Russian forces fighting in Ukraine.