KIEV, May 7 -- At least 14 Ukrainian soldiers have been killed since the start of the government's "anti-terror" operation in the country's eastern regions, authorities said Wednesday.

According to the Security Bureau's press service, about 66 Ukrainian troops were wounded in confrontations with pro-Russian activists during the military operation to retake the cities and towns seized by protesters.

Since the operation began on April 13, there were also casualties among pro-Russian activists, but authorities did not provide a figure.

Currently, the "counter-terror" measures are underway in several towns in Donetsk region. Earlier in the day, government forces had retaken the administrative building in Mariupol town.

Ukraine suspended its military operation on April 20 following an agreement with Russia, the U.S. and the European Union in Geneva, which calls for all sides of the conflict to refrain from violence.

Three days later, Kiev resumed the active phase of the operation after pro-Russian activists allegedly kidnapped and tortured several journalists and public figures in Donetsk region.