"There is no longer any disguise...as part of its outright genocidal war, the Russian Federation for the first time struck at the territory of Ukraine with missiles received from...North Korea," Podolyak wrote on X social media.

Podolyak did not provide evidence for the missiles being North Korean. In its statement on Thursday, Washington cited declassified intelligence.

"(Russia) is attacking Ukrainians with missiles received from a state where citizens are tortured in concentration camps for having an unregistered radio, talking to a tourist, watching TV shows," Podolyak said.

There was no immediate comment from Moscow.

Earlier on Friday, state media quoted the governor of the eastern Ukrainian region of Kharkiv as saying missiles produced outside Russia had been fired into the province at the end of December and beginning of January.

Kharkiv region prosecutors said they were conducting an investigation into the country of origin of three missiles used by Russia to hit the provincial capital on Tuesday. Their statement did not name North Korea.

That attack on Kharkiv city killed two people and wounded 62, the prosecutor's office said.

Ukraine's air force said earlier on Friday it could not yet confirm the country of manufacture of the missiles in question.

While the United States would not say specifically what type of missiles Pyongyang had sent to Russia, U.S. spokesman John Kirby said they had a range of about 900 km (550 miles). He released a graphic that appeared to show KN-23 and KN-25 short-range ballistic missiles (SRBMs).

North Korea has been under a United Nations arms embargo since it first tested a nuclear bomb in 2006.

U.N. Security Council resolutions - approved with Russian support - ban countries from trading weapons or other military equipment with North Korea.

In November, South Korean authorities said North Korea may have supplied SRBMs to Russia as part of a larger arms deal that also included anti-tank and anti-air missiles, artillery and mortar shells, and rifles.

Both Moscow and Pyongyang have previously denied conducting any arms deals, but vowed last year to deepen military relations.

(Reporting by Max Hunder and Yuliia Dysa; Editing by Alex Richardson and Angus MacSwan)