"The incident occurred at around 14:30 on 24 February in ‘DPR’-controlled Yasynuvata, north of Donetsk city. An SMM patrol was attempting to launch a UAV, intending to monitor the alleged shelling of the Donetsk water filtration station, when armed men pointed their weapons at them, advanced towards them and seized the UAV, after which one of the men opened fire which impacted close to the SMM patrol," reads the report.

Read alsoOSCE SMM concerned over threat of eco-disaster as Donetsk water filtration station halts operations"Firing at unarmed civilian monitors is not only a direct threat to the lives of brave men and women doing their best to bring peace to Ukraine," Apakan said, "it is a direct challenge to the collective will of the 57 OSCE participating States, and to the Minsk agreements."

Apakan insisted that those responsible be held accountable and that there should be no impunity for these acts.

"Threatening SMM monitors and otherwise impeding the work of the SMM serves only to delay resolution of the conflict," he said.