President Vladimir V. Putin of Russia and North Korea’s leader, Kim Jong-un, revived a Cold War-era mutual defence pledge between their nations on Wednesday, signing a new agreement that calls for them to assist each other in the event of “aggression” against either country.

The Russian President, in a briefing after the two leaders signed the document, did not clarify whether such assistance would require immediate and full-fledged military intervention in the event of an attack, as the now-defunct 1961 treaty specified. But he said that Russia “does not exclude the development of military-technical cooperation” with North Korea in accordance with the new agreement.

The pact was one of the most visible rewards Kim has extracted from Moscow in return for the dozens of ballistic missiles and over 11,000 shipping containers of munitions that Washington has said North Korea has provided in recent months to help support Putin’s war in Ukraine.

It also represented the farthest the Kremlin has gone in throwing its weight behind North Korea, after years of cooperating with the US at the UN in curbing Pyongyang’s nuclear and missile programme — a change that accelerated after Russia’s invasion of Ukraine.

“This is a truly breakthrough document, reflecting the desire of the two countries not to rest on their laurels, but to raise our relations to a new qualitative level,” Putin added. Neither North Korea nor Russia immediately released the text of the new agreement.

Putin denounced the US for expanding military infrastructure in the region and holding drills with South Korea and Japan.

He rejected what he called attempts to blame the deteriorating security situation on North Korea, which has carried out six nuclear test explosions since 2006 and tested intercontinental ballistic missiles that could reach the US.

“Pyongyang has the right to take reasonable measures to strengthen its own defence capability, ensure national security and protect sovereignty,” Putin said.

Kim called the pact a “most powerful agreement” and praised the “outstanding foresight” of Putin, “the dearest friend of the Korean people”, the state-owned Russian news agency RIA Novosti said.

New York Times News Service