TOKYO (Reuters) - A coal-fired power plant supplying half of Japan’s northern Hokkaido island was damaged in a powerful earthquake that struck earlier on Thursday, the country’s industry ministry said.

Hokkaido Electric Power 9509.T, the plant's operator, said earlier it shut down all its remaining fossil fueled plants in the immediate aftermath of the quake, leaving all of its 2.95 million customers without power.

The 350 megawatt (MW) capacity No.1 unit and the 600 MW No.2 unit at the Tomato-Atsuma plant operated by Hokkaido Electric Power 9509.T have been damaged, the ministry said, without specifying the nature of the damage.

Hokkaido Electric is preparing to restart the plant’s 700 MW No.4 unit, the ministry said, without saying when power supplies would resume.