WASHINGTON, Sep 11 (Aljazeera) – As Russian President Vladimir Putin prepares to meet North Korean leader Kim Jong Un, the United States has threatened to “aggressively” enforce existing sanctions and add new ones if Pyongyang provides weapons to Moscow for its war in Ukraine.

US State Department spokesperson Matthew Miller said on Monday that the US will continue to “hold accountable” entities that help Russia’s military campaign in Ukraine.

“I will remind both countries that any transfer of arms from North Korea to Russia would be in violation of multiple United Nations Security Council resolutions,” Miller told reporters.

“We, of course, have aggressively enforced our sanctions against entities that fund Russia’s war effort, and we will continue to enforce those sanctions and will not hesitate to impose new sanctions if appropriate.”

He did not specify whether the US would impose penalties on North Korea, Russia or both, saying that the US is monitoring the situation and will “wait and see what the outcome of the meeting is before speculating”.

Both Russia and North Korea are already under heavy US sanctions. Moscow and Pyongyang have confirmed that Putin and Kim are set to meet in the coming days.

On Monday, the Russian president travelled to attend an economic forum in the far eastern Pacific port city of Vladivostok, where he met Kim in 2019.

Miller argued that, by turning to Kim — an “international pariah” — for help, Putin is showing that his full-scale invasion of Ukraine in 2022 was a “strategic failure”.

“There’s no better evidence of that than now. A year and a half later, not only has he failed to achieve his goals on the battlefield, but you see him travelling across his own country, hat in hand, to beg Kim Jong Un for military assistance,” Miller said on Monday.

After failing to capture the Ukrainian capital in the early weeks of the invasion, Russia has limited its war goals to occupying eastern parts of the country. Ukraine launched a counteroffensive earlier this year but has only made modest gains against Russian forces.

“We continue to assess that the Ukrainians are making progress in their counteroffensive, and we have confidence in the ability of their forces,” Miller said.

The US, which provides billions of dollars in aid to Ukraine, has been warning its competitors and adversaries — including China — against helping Russia in its military offensive.

In the past two weeks, Washington has repeatedly urged Pyongyang against selling arms to Moscow.

When asked on Monday why the US is concerned that the Kim-Putin meeting would be about a weapons deal, Miller responded that it is not a “social gathering”.

Russia and North Korea have signalled that their relations have grown closer in recent months. In July, for example, Russia’s Defence Minister Sergei Shoigu visited North Korea — the first time a Russian defence chief had done so since 1991. While there, Shoigu met with Kim to discuss “strategic and tactical collaboration”.

Kim and Putin also exchanged letters last month vowing to bolster cooperation between their two countries.

Last year, the US also accused North Korea of covertly shipping artillery shells to Russia, an allegation that was denied by both Moscow and Pyongyang.

Separately, tensions have been intensifying between Pyongyang and Washington over North Korea’s nuclear programme and increased missile testing. North Korea has framed these missile launches as a defensive response to joint US military drills with South Korea and Japan near the Korean Peninsula.