Seoul — Major weapons exporter South Korea will “reconsider” a longstanding policy that bars it from supplying arms directly to Ukraine, a presidential official said Thursday, after North Korea and Russia signed a defense deal. Russia’s President Vladimir Putin was in Pyongyang Wednesday for a high-profile state visit that underscored his growing ties with leader Kim Jong Un, as the two signed a “breakthrough” agreement that included a pledge to come to each other’s aid if attacked.

Hours later, Seoul said it was “planning to reconsider the issue of providing weapons support to Ukraine,” a presidential official told reporters.

Seoul has a longstanding policy that bars it from selling weapons into active conflict zones, which it has stuck to despite calls from Washington and Kyiv to reconsider.

The country, which is aiming to become one of the world’s top arms exporters, has signed billions of dollars of deals to sell its tanks and howitzers to European countries, including Kyiv’s ally Poland.

Seoul expressed its “grave concern” over the Moscow-Pyongyang agreement, where the two countries agreed to strengthen their military and economic cooperation, including immediate military assistance if either faced armed aggression.

“Any cooperation that directly or indirectly helps strengthen North Korea’s military capabilities is a violation of the U.N. Security Council resolutions,” national security adviser Chang Ho-jin told reporters. “Russia’s own violation of the resolution and support for North Korea will inevitably have a negative impact on the South Korea-Russia relationship.”

Putin said in Pyongyang that Russia “does not rule out military-technical cooperation” with the North, which would violate rafts of U.N. sanctions on Kim’s regime over his banned nuclear and ballistic missile programs.

North Korea and Russia have been allies since North Korea’s founding after World War II and have drawn even closer since Russia’s 2022 invasion of Ukraine, as Western powers have stepped up sanctions against Moscow. 

CBS News senior foreign correspondent Elizabeth Palmer said that while the pact signed Wednesday in Pyongyang saw Putin and Kim pledge to defend the other if attacked, officials in the U.S. and other Western capitals believe Russia, above all, wants to ensure a steady supply of North Korean weapons for its war in Ukraine. Concern has grown for months, however, over a tacit arms arrangement in which North Korea provides Russia with munitions in exchange for economic assistance and technology transfers, which politicians and experts fear could enhance the threat posed by Kim’s nuclear weapons and missile program.

Pyongyang has described allegations of supplying weapons to Russia as “absurd,” but the new treaty between the North and Moscow has fueled concerns of increased weapons deliveries. 

North Korea thanked Russia for using its U.N. veto in March to effectively end monitoring of sanctions violations, just as U.N. experts were starting to probe alleged arms transfers.

During the state visit, Kim called Putin the “dearest friend of the Korean people” and said his country “expresses full support and solidarity to the Russian government” over the war in Ukraine.

Putin also said that the U.N. sanctions against the North — which began in 2006 over the country’s banned nuclear programs — should be reviewed.

Seoul said Thursday it will slap additional unilateral sanctions against a number of Russian and North Korean parties over arms shipments and oil transfers between the two countries.

Any future weapons support from Seoul to Ukraine would need to “involve a clear level of moderation,” Ahn Chan-il, a defector-turned-researcher who runs the World Institute for North Korea Studies, told AFP.

“If the support is limited to conventional weapons such as artillery shells and landmines, similar to the level of support North Korea is providing to Russia, the backlash from Russia could be minimized,” he added.