The Russian-annexed nation of Crimea is under a state of emergency after four electricity transmission towers located in Ukraine were damaged by bombs in two different attacks. Approximately 1.6 million people are without power.

At this time, officials are unclear on who attacked the pylons, but Russian authorities stated it was “an act of terrorism,” according to Voice of America News. And while Russian officials didn’t directly place blame, they implied Ukrainian nationalists may have been behind the attacks. The attacked pylons are located in Ukraine, where Crimea gets the majority of its electricity supplies.

The attacks were a couple days apart with two of the pylons being hit on Friday and the next two being hit Sunday. The Washington Post reports that more than a quarter of the population, mostly in major cities, had their power restored through the use of mobile gas turbine generators by Sunday afternoon. However, there are still many without power, and the Crimean government said it would come up with a schedule for supplying electricity and water to homes without power.

But repairs were delayed when Ukrainian activists took the roads on Saturday and attempted to block the trucks from getting to the damaged towers. However, they retreated after clashes with the police, according to Voice of America News.

Crimea was annexed in 2014 by Russia after pro-Western Ukrainian protests forced President Viktor Yanukovych from office. Weeks later, a rebel group that wanted to separate from Russia, launched a large enough rebellion that trade and travel sanctions were placed on key Russian officials. Voice of America News reports that the U.N. announced in September that nearly 8,000 people, mostly civilians, have been killed in the conflict.