MOSCOW (AP) — Russia’s top diplomat shrugged off U.S. claims that North Korea transferred munitions to Russia, saying Washington has failed to prove the allegation.

Russian state television broadcast Foreign Minister Sergey Lavrov’s comments on Friday. Lavrov made a two-day trip to Pyongyang this week for talks on ways to boost the two countries’ ties following a September summit between North Korean leader Kim Jong Un and Russian President Vladimir Putin.

The White House said last week that North Korea had delivered more than 1,000 containers of military equipment and weapons to Russia. It released images that it said showed the containers were loaded onto a Russian-flagged ship before being moved via train to southwestern Russia.

White House National Security Council spokesman John Kirby said the U.S. believes Kim is seeking sophisticated Russian weapons technologies in return for the munitions to boost North Korea’s military and nuclear program.

Lavrov scoffed at the U.S. claims, saying that “the Americans keep accusing everyone.”

“I don’t comment on rumors,” he added.

Since last year, the U.S. has accused North Korea of providing ammunition, artillery shells and rockets to Russia for the fighting in Ukraine. North Korea has steadfastly denied it shipped arms to Russia. South Korean officials charged that weapons North Korean provided already were used in Ukraine.

When Kim visited Russia for six days last month, a trip that included meeting with Putin, Russian and North Korean officials said that boosting defense ties between the two countries was discussed but they didn’t disclose any specific steps.

On Thursday, Lavrov and Kim exchanged views on joint efforts to expand bilateral ties in all areas and discussed other key issues of mutual concern, the North’s official Korean Central News Agency reported. It said Kim expressed his resolve to carry out unspecified agreements he reached with Putin.

Lavrov described the talks as “comprehensive” and said, “We have an understanding on how to proceed to fulfill the agreements” between Putin and Kim.

After he arrived in Pyongyang, Lavrov gave a speech in which he said that Russia deeply valued North Korea’s “unwavering and principled support” for its military operation in Ukraine. Back in Moscow, he stressed that the effort to deepen the relationship between Russia and North Korea was based on bilateral concerns.

“Our friendship isn’t directed against anyone. It’s intended to help promote mutually beneficial projects,” he said.

Lavrov also told reporters that he supports holding regular talks on security issues on the Korean Peninsula with North Korea and China.