North Korean troops recently deployed to help Russia in its war with Ukraine have come under Ukrainian fire, a Kyiv official said Tuesday.

It is the first time a Ukrainian official has said that Pyongyang’s units were struck, following a deployment that has given the war a new complexion as it approaches its 1,000-day milestone.

“The first North Korean troops have already been shelled, in the Kursk region,” Andrii Kovalenko, the head of the counter-disinformation branch of Ukraine’s Security Council, wrote on Telegram. He provided no further details.

Western governments had expected that the North Korean soldiers would be sent to Russia’s Kursk border region, where a 3-month-old incursion by the Ukrainian army is the first occupation of Russian territory since World War II and has embarrassed the Kremlin.

U.S., South Korean and Ukrainian intelligence assessments say up to 12,000 North Korean combat troops are being sent by Pyongyang to the war under a pact with Moscow.

The North Korean troops, whose fighting quality and battle experience is unknown, are adding to Ukraine’s worsening situation on the battlefield.

Ukrainian defenses, especially in the eastern Donetsk region, are buckling under the strain of Russia’s costly but relentless monthslong onslaught.

Russian advances have recently accelerated, with battlefield gains of up to 9 kilometers (more than 5 miles) in some parts of Donetsk, the U.K. Defense Ministry said Tuesday on the social platform X.

It said Russia has superior troop numbers, and despite heavy casualties the Kremlin’s recruitment drive is providing enough new troops to keep up the pressure.

Russia has held the battlefield initiative in Ukraine for the past year. Ukrainian officials have long complained that Western military support takes too long to arrive in the country.

In early October, Russian forces drove Ukrainian troops out of Vuhledar, a town perched atop a tactically significant hill in eastern Ukraine.

likely are the key logistics hub of Pokrovsk and the strategically important city of Chasiv Yar.

In the meantime, Russia has kept up its long-range aerial attacks on civilian areas of Ukraine, authorities say.

A Tuesday morning attack on the southern city of Zaporizhzhia killed six people and injured 16 others, regional Gov. Ivan Fedorov said.

The head of Ukraine’s presidential office, Andrii Yermak, said the Russian attacks “must be stopped with strong action.”

“A stronger position by (Ukraine’s Western) allies is needed,” he wrote on Telegram.