Two US citizens died recently in the Donbas region of eastern Ukraine, a US State Department spokesman said on Saturday, without giving further details.

The US administration was in contact with the families of the deceased and was offering "all possible consular assistance", said the spokesperson of the State Department, Telegraph reports.

The spokesman declined to say when exactly they died or their circumstances.

"Out of respect for the families during this difficult time, we have nothing further," said the spokesman, who was confirming an earlier CNN report.

Ukraine has been under siege by Russia for nearly five months in what Moscow calls a "special military operation" to disarm Ukraine and rid it of anti-Russian nationalism.

Kiev and the West say Russia launched an unprovoked war.