The White House is urging North Korea to “not provide or sell arms to Russia” as Pyongyang and Moscow said Monday that Kim Jong Un would travel to Russia at the invitation of Vladimir Putin.

“As we have warned publicly, arms discussions between Russia and the DPRK are expected to continue during Kim Jong-Un’s trip to Russia,” said National Security Council spokesperson Adrienne Watson in response to Russia and North Korea’s announcement. “We urge the DPRK to abide by the public commitments that Pyongyang has made to not provide or sell arms to Russia.”

Just last week, the US warned Kim Jong Un might travel to Russia to discuss a potential deal to provide weapons to the country as it wages its war in Ukraine, and the White House has said arms negotiations between the two countries are “actively advancing.”

Some context: North Korea is already under United Nations and US sanctions imposed over Pyongyang’s weapons of mass destruction program.

The potential Putin-Kim meeting could lead to Pyongyang getting its hands on the sort of weapons those sanctions have barred it from accessing for two decades, especially for its nuclear-capable ballistic missile program.

It also comes after more than a year and a half of war in Ukraine has left the Russian military battered, depleted and in need of supplies.