North Korea demonstrated this year that it could produce ballistic missiles and supply them to Russia for use against Ukraine in a matter of months.

Far from their homes in one of the world’s most isolated and secretive states, about 11,000 North Korean soldiers find themselves at the center of Europe’s biggest conflict since World War II.

Sending troops to fight against Ukraine has gotten North Korea much-needed cash and diplomatic leverage. But there may be hidden costs, too.

Jonah Leff, who heads Conflict Armament Research (CAR), an independent organization that tracks weapons used in conflicts, said his researchers documented remnants of four missiles they assess came from North Korea that were recovered in July and August in Ukraine. He said one of the missiles had markings indicating it was produced this year.

The United States on Monday issued fresh North Korea-related sanctions involving financial institutions, the Treasury Department website showed.

The Pentagon has seen “indications” that the North Korean forces who have been sent to Russia to help the Kremlin in its war against Ukraine have suffered their first casualties, according to a U.S. official.

U.S. confirms North Korean troop casualties in Russia, with reports of efforts to conceal losses through cremation by Russian forces.