The United States ambassador to South Korea on Wednesday slammed Russia over alleged discussions with North Korea on military cooperation, amid signs of growing military ties between Pyongyang and Moscow.

"What Russia appears to be doing with the DPRK is not just a violation of the very resolutions it voted for, but is dealing in weaponry and discussions of military cooperation with a regime that has flouted every aspect of international rule of law," Ambassador Philip Goldberg said in a group interview with reporters at his official residence in central Seoul.

DPRK stands for the Democratic People's Republic of Korea, North Korea's official name.

The comments came in light of last month's meeting between North Korean leader Kim Jong-un and Russian Defense Minister Sergei Shoigu during the Moscow official's visit to Pyongyang. The two sides are believed to have reached "a broad framework" of agreements on military cooperation.

Last week, the US Department of the Treasury's Office of Foreign Assets Controls imposed sanctions on three entities involved in illicit arms deals between North Korea and Russia, amid speculation that the countries may be seeking to bolster their illegal arms trade.

On North Korea's announced plan to launch a spy satellite in the coming weeks, Goldberg said Seoul and Washington, along with Tokyo, "would coordinate" in dealing with the space launch if it should take place.

"I want to stress, these tests, what the DPRK is proposing to do and did unsuccessfully with the space launch the last time, it falls under the U.N. (Security Council) resolutions and is a violation of them," Goldberg said.

Pyongyang launched its first military spy satellite, the Malligyong-1, mounted on a new type of rocket named the Chollima-1, on May 31. But the rocket crashed into the Yellow Sea after an "abnormal starting" of the second-stage engine, according to the North's state media.

Goldberg, however, stated that the "door is very much open to negotiations" if Pyongyang so chooses. "We hope that China will urge the DPRK to return to negotiations."

On recent summit agreements reached by leaders of South Korea, the US and Japan at Camp David last week, the ambassador said the outcome of the meeting is not about creating a "new NATO."

"This is a cooperative and collaborative agreement between three democratic countries with shared interests and values in a whole wide range of areas," Goldberg said.

President Yoon Suk Yeol and his US and Japanese counterparts, Joe Biden and Fumio Kishida, respectively, adopted a series of documents committing each other to sturdier three-way cooperation during their historic summit at Camp David in Maryland on Friday, underscoring their deepening solidarity amid North Korea's saber-rattling, China's assertiveness and Russia's war in Ukraine.

The documents entailed agreements to consult with one another in the event of a common threat, and hold three-way talks between the leaders, foreign ministers, defense ministers and national security advisers at least annually, as well as an intention to hold annual "multidomain" military exercises on a regular basis. (Joint Press Corps-Yonhap)