An American paramedic who died in an explosion while working with international monitors in eastern Ukraine might have been the target of a false flag attack, according to the Russian government.

“The Foreign Ministry is outraged by the cynical act that resulted in a human casualty and targeted international monitors whose efforts are aimed at achieving peace,” Russian Foreign Minister Sergey Lavrov’s team said late Sunday. “We call for a thorough and unbiased investigation and holding the perpetrators accountable.”