According to White House National Security Spokesperson John Kirby, the U.S. has intelligence that suggests North Korea is discretely providing Russia with a "significant" amount of artillery shells for its war in Ukraine.

"Our indications are that the DPRK is covertly supplying and we are going to monitor to see whether the shipments are received," Kirby said.

North Korea was trying to conceal the shipments by routing them through nations in the Middle East and North Africa, Kirby said in a virtual briefing.

"We do have a sense of where they are going to transfer these shells," Kirby added.

Ned Price, a spokesperson for the U.S. State Department, urged penalties during a routine news briefing, as he had done in the past when Iran supplied Russia with weapons.

"Just as we're using every tool and will use every tool to counter the Iranian provision of weapons to Russia, we will do the same when it comes to the DPRK's provisions of weapons to Russia," he said.

"There are existing sanctions on the books," he added. We will look at additional tools and authorities that we may be able to call upon to counter this activity."

In September, the U.S. imposed sanctions on three other firms it claimed were engaged in the manufacture of Iranian drones as well as an Iranian corporation it accused of organizing military flights to deliver Iranian drones to Russia. Although not insignificant, the number of shells, according to Kirby, was not likely to have a substantial impact on the war's course or result. He added that they might still be fatal for Ukrainians.

The North Korean supplies, according to Kirby, were a sign of Moscow's ammunition shortages imposed on by U.S.-led sanctions and export limits as well as Pyongyang's desire to back Russia. 

North Korea warned the United States to "keep its mouth shut" and cease spreading allegations intended to tarnish the country's reputation in September, asserting that it has never provided Russia with weapons or ammunition and has no plans to do so.

The U.S. would make sure it has the capacity there to defend its partners, Kirby said in reference to the Wednesday missile tests by North Korea, adding that they did not constitute an imminent threat to U.S. forces in the area.

On Wednesday, North Korea launched at least 23 missiles into the ocean, one of which came down less than 60 kilometers off the shore of South Korea, an act the country's president, Yoon Suk Yeol, referred to as "territorial encroachment."