Pyongyang, North Korea - A Russian delegation led by natural resources minister Alexander Kozlov has left Pyongyang after a two-day visit, North Korea's state media said Friday, with the two countries' growing cooperation triggering concern in Washington and Seoul.

The visit came after US Secretary of State Antony Blinken warned this month that ties between Pyongyang and Moscow were "growing and dangerous," urging the North's ally China to restrain the nuclear-armed country.

The delegation arrived in Pyongyang on Tuesday and left on Thursday, the official Korean Central News Agency reported, to discuss "cooperation in trade, economy, science, and technology."

Russian and North Korean flags fluttered at the airport in Pyongyang as high-level North Korean officials saw the delegation off, KCNA said.

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Historic allies Russia and North Korea are both under international sanctions – the former for its invasion of Ukraine and the latter for its nuclear weapons and missile programs.

South Korea accuses Pyongyang of having provided over one million artillery rounds to Moscow for use in its war with Ukraine. Seoul says the North appears to have received advice on military satellite technology in return.

The latest Russian visit comes after the G7's top diplomats last week slammed the arms transfers, urging North Korea and Russia to "immediately cease all such activities."

The two countries have ramped up cooperation following North Korean leader Kim Jong Un's summit with Russian President Vladimir Putin in September.

Kim had traveled to Russia aboard a special bullet-proof train, declaring bilateral ties with Moscow were his country's "number one priority."

The two countries wish to develop cooperation in accordance with the agreements reached at the September summit, KCNA said Wednesday.

KCNA also said Wednesday that a North Korean delegation headed by the country's sports and culture minister left to attend a forum in the Russian city of Perm.

Analysts say the latest moves indicate both countries are keen to emphasize their growing alliance, despite global criticism.