SEOUL, Jun. 24 (Yonhap) – South Korea, the United States and Japan on Monday condemned "in the strongest possible terms" the expanding military cooperation between Russia and North Korea, days after the signing of the two isolated states' new treaty on mutual defense aid at the leaders' summit last week.

The joint statement came after Russian President Vladimir Putin and North Korean leader Kim Jong-un signed the "comprehensive strategic partnership" treaty during Putin's visit to Pyongyang on Wednesday.

The treaty calls for the provision of military and other assistance from one side to the other "with all means" at its disposal and "without delay," if either of the two gets invaded or put in a state of war.

"The United States, ROK, and Japan condemn in the strongest possible terms deepening military cooperation between the DPRK and Russia, including continued arms transfers from the DPRK to Russia that prolong the suffering of the Ukrainian people, violate multiple United Nations Security Council Resolutions, and threaten stability in both Northeast Asia and Europe," the statement read.

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

The three countries said that the new treaty between Moscow and Pyongyang should be of "grave concern" to all concerned parties that uphold the non-proliferation regime.

They reaffirmed their commitment to strengthening cooperation to counter the threats posed by the North and prevent the escalation of the situation.

The U.S. said that its commitment to the defense of Korea and Japan remains "ironclad."

"The United States, ROK and Japan also reaffirm that the path to dialogue remains open and urge the DPRK to cease further provocations and return to negotiations," it said.

The statement was issued under the names of Jung Pak, the U.S. senior official for North Korea; Cho Koo-rae, the South Korean vice foreign minister; and Namazu Hiroyuki, assistant minister for Asian and Oceanian Affairs at Japan's foreign ministry.

Photo from Yonhap