The US has input that North Korea is secretly supplying Russia with a "substantial" number of artillery shells for its assault in Ukraine, according to White House National Security Spokesperson John Kirby.
Kirby said in a video briefing that North Korea was seeking to conceal the shipments by routing them through Middle Eastern and North African countries.
"Our sources are that North Korea is covertly supplying artillery shells and we will monitor to see if the shipments are received," Kirby said, adding that Washington would speak with the UN on accountability issues about the shipments.
"We have a doubt of where they are going to transport these shells," Kirby said, declining to provide any further details as the US considers its options.
At a routine news briefing, US State Department spokesman Ned Price said that sanctions, like in the case of Iran's transfer of weapons to Russia, were among the choices.
“Just as we are using and will continue to use every means to resist Iran's transfer of weapons to Russia, we will also do the same when it comes to North Korea providing weapons to Russia,” he said.
The US imposed sanctions in September on an Iranian business suspected of organising military flights to deliver Iranian drones to Russia, as well as three other companies involved in the development of Iranian drones.
Kirby said that it was unlikely to influence the momentum or result of the war. However, he believes they could still be lethal to Ukrainians.
"And it's certainly not going to change our equations…or the calculus of so many of our allies and partners about the types of capabilities we'll continue to supply the Ukrainians," he added.
According to him, the North Korean supplies demonstrate not only Pyongyang's willingness to back Russia but also Moscow's ammunition shortages caused by US-led sanctions and export curbs.
North Korea declared in September that it has never sent weapons or ammunition to Russia and has no plans to do so while advising the US to "keep its mouth shut" and stop spreading misinformation that "tarnishes" the country's image.