One of the two American citizens who recently died in the Donbas region of Ukraine has been identified as Luke Lucyszyn, his mother told CNN.

Kathy Lucyszyn said she was informed of her son's death by the US State Department.

The State Department confirmed the deaths of two Americans to CNN on Saturday, but a spokesperson did not provide any details about the individuals or the circumstances. The spokesperson said they had been “in touch with the families and providing all possible consular assistance.”

Politico first reported that Lucyszyn was killed.

Asked Saturday about the condition of Alexander Drueke and Andy Hunyh, two Americans captured by Russian forces while fighting in Ukraine, the spokesperson said they had “been in contact with the Ukrainian and Russian authorities regarding U.S. citizens who may have been captured by Russia's forces or proxies while fighting in Ukraine.”

“We call on Russia to live up to its international obligations to treat all individuals captured fighting with Ukraine's armed forces as prisoners of war,” they said. (CNN)