Russian missile attacks on state-owned natural gas assets in Ukraine have forced the country to buy expensive replacement fuel from the European Union, according to people with knowledge of the matter.

Though North Korean ballistic missiles account for only a small portion of Russia's missile strikes they carry a large warhead of up to one tonne and have a range of up to 800 km, the military source said. The Iskander-M, an equivalent Russian missile, carries a smaller payload and has a shorter range of 500 km.

A Russian strike killed five civilians and wounded 55 on Tuesday in the town of Izium in Ukraine's northeastern Kharkiv region, partially destroying the city council building, officials said.

At least four people died overnight as Russian drone and missile strikes continued to pound Ukraine’s towns and cities, local officials said Saturday. Meanwhile, Moscow’s troops continued their grinding advance through the country’s east.

North Korean troops, largely special ops forces, have suffered high casualties in bloody assaults not unlike other units, including prison units.

North Korean missiles used by Russia in attacks on Ukraine since December have become more accurate, Reuters reported on Feb. 6, citing sources familiar with the matter. Analysts believe North Korea is using the battlefield as a testing ground for its missile technology,

Experts say Pyongyang’s advancing missile technology raises global security risks and threatens regional stability.