WASHINGTON 

Russia used ballistic missiles supplied by North Korea in a series of attacks on Ukraine during the New Year holiday, and is working on brokering another deal with Iran for additional arms, the White House said Thursday.

The transfer of ballistic missile launchers and "several" missiles from Pyongyang occurred "recently," National Security Council spokesperson John Kirby told reporters.

At least one was launched Dec. 30 and landed in an open field in the Zaporizhzhia region. Another launch that involved multiple North Korean missiles occurred Jan. 2.

The US is still assessing the effects of the missiles that were fired Tuesday, but the Biden administration believes that Russia and North Korea will learn from the launches and that Moscow will carry out additional attacks.

"This is a significant and concerning escalation in the DPRK's support for Russia," said Kirby, referring to North Korea by its formal acronym. "We anticipate that Russia will use additional North Korean missiles to target Ukraine's civilian infrastructure and to kill innocent Ukrainian civilians."

The missiles that were fired have ranges of up to 900 kilometers (560 miles), according to the White House.

Kirby said North Korea continues to seek a wide array of military equipment in return for its supplies of weapons, including fighter jets, surface-to-air missiles, armored vehicles, equipment to build additional ballistic missiles and other advanced technologies.

Meanwhile, Moscow is continuing negotiations with Iran to acquire short-range ballistic missiles to help replenish its war stocks, and while the US has not yet determined that a deal has been reached, it is concerned that the talks "are actively advancing," said Kirby.

Russia's alleged efforts to bolster its stocks come as US President Joe Biden's October request for more than $60 billion in military assistance for Ukraine continues to languish in Congress. His administration has repeatedly warned that it has run out of congressionally-appropriated funds to aid Kyiv's forces.

"The most effective response to Russia's horrific violence against the Ukrainian people is to continue to provide Ukraine with vital air defense capabilities and other types of military equipment. To do that, we need Congress to approve our supplemental funding request for Ukraine without delay," said Kirby.

"Russia is relying upon its friends to replenish its military stockpiles, and enable its war against Ukraine. Iran and the DPRK are standing with Russia. Ukrainians deserve to know that the American people, and this government, will continue to stand with them," he added.

Linda Thomas-Greenfield, Washington's envoy to the UN, maintained that the Biden administration will not "stay silent" in the face of North Korea's arms transfer to Russia, which run afoul of multiple UN Security Council resolutions.

"The United States will continue to work with allies and partners to identify, expose, and counter the Russian government’s attempts to acquire military equipment from the DPRK or any state that is prepared to support the Kremlin’s war in Ukraine," she added.

North Korea has been under a sweeping UN arms embargo since 2006. It has been repeatedly tightened states to now include the import and export of nearly all types of weapons.

Pyongyang's recent transfer of arms is slated to be addressed by the UN Security Council on Jan. 10, according to Thomas-Greenfield.