A lightning strike caused the shutdown of Armenia's single nuclear power plant, Interfax news agency reported on Saturday, citing local authorities.
The plant was hit at 9:55 p.m. (1755 GMT) on Friday and was disconnected from the grid, the report cited the ministry of territorial administration and infrastructure as saying.
The plant, about 25 km (15 miles) outside the capital Yerevan, is supervised by the Armenian government.
"The reason was a lightning strike, which caused the station's safety systems to switch it into safe shutdown mode," it said.
The ministry said personnel were working to restart the plant, according to Interfax.