KYIV, Ukraine — North Korean troops are suffering heavy losses in the fighting in Russia’s Kursk region and facing logistical difficulties as a result of Ukrainian attacks, Ukraine’s military intelligence said Thursday.

The intelligence agency, known by its acronym GUR, said Ukrainian strikes near Novoivanovka inflicted heavy casualties on North Korean units. It said North Korean troops also faced supply issues and even drinking water shortages.

Ukrainian President Volodymyr Zelenskyy said earlier this week that 3,000 North Korean troops have been killed or wounded in fighting in the Kursk region. It marked the first significant estimate by Ukraine of North Korean casualties several weeks after Kyiv announced that North Korea had sent 10,000 to 12,000 troops to Russia to help it in the almost 3-year-old war.

The casualty disclosure came as the Biden administration was pressing to send as much military aid as possible to Ukraine before President-elect Donald Trump takes office Jan. 20.

Ukrainian military forces launched an incursion into the Kursk region in August, dealing a significant blow to Russia’s prestige and forcing it to deploy some of its troops from eastern Ukraine, where they were pressing a slow-moving offensive.

The Russian army has been able to reclaim some territory in the Kursk region from Ukrainian forces, but it has failed to fully dislodge them.

At the same time, Russia has sought to break Ukraine’s resistance with waves of strikes by cruise missiles and drones against Ukraine’s power grid and other infrastructure.

The latest attack on Christmas morning involved 78 missiles and 106 drones, striking power facilities, Ukraine’s air force said. It claimed to have intercepted 59 missiles and 54 drones and jammed 52 other drones.

On Thursday, Russia attacked Ukraine with 31 exploding drones. Twenty were shot down and 11 others didn’t reach their target due to jamming, the Ukrainian air force said.

As part of the daily barrage, Russian forces struck a central market in Nikopol in the Dnipropetrovsk region with a drone, wounding eight people, according to local authorities.

Russian President Vladimir Putin threatened Thursday that Russia could again hit Ukraine with the new Oreshnik hypersonic ballistic missile that was first used in a Nov. 21 strike on the Ukrainian city of Dnipro.

“We aren’t in a rush to use them because those are powerful weapons intended for certain tasks,” he said. “But we wouldn’t exclude their use today or tomorrow if necessary.”

Putin reaffirmed a plan to deploy some of Oreshnik missiles in Russia’s neighbor and ally Belarus. Belarus’ authoritarian President Alexander Lukashenko told reporters Thursday that his country could host 10 or more.

Ukraine struck back with drone strikes of its own. Ukraine’s Center for Strategic Communications said the military struck a plant in Kamensk-Shakhtynsky in Russia’s Rostov region that produces propellant for ballistic missiles.