FILE PHOTO - A vehicle of the Organization for Security and Cooperation in Europe (OSCE) special monitoring mission for Ukraine drives past the OSCE office in the pro-Russian rebel-held city of Luhansk, Ukraine, April 24, 2017. REUTERS/Alexander Ermochenko

WASHINGTON (Reuters) - The U.S. State Department said on Thursday it was “deeply concerned” about a pattern of violence by Russian-backed separatists in eastern Ukraine targeting unarmed civilians of a European mission monitoring the conflict in region.

State Department spokeswoman Heather Nauert said members of a special monitoring mission of the Organization for Security and Cooperation in Europe were harassed, threatened and ultimately fired upon on June 20. A U.S. medic serving with the monitors was killed in April when his truck hit an explosive.

“The incidents are part of a broader effort to keep the international community from seeing what is happening in Eastern Ukraine,” Nauert said. “We call on Russia to use its influence to end this campaign of intimidation and honor its commitment to

allow free, full and safe access to the OSCE monitors.”