TOKYO - Tokyo Electric Power Co said pressure inside the No.1 reactor at its Fukushima-Daiichi nuclear plant has been rising, with the risk of a radiation leak, Jiji News reported on Saturday.
TEPCO plans to take measures to release the pressure, the report added. No comment was immediately available from TEPCO.
The plant's cooling system malfunctioned after a strong earthquake hit northeast Japan.
US President Barack Obama said Japan's Prime Minister Naoto Kan told him during a phone call that so far there were no signs of a radiation leak at the Japanese nuclear plant.
Japan has declared a state of atomic power emergency and is evacuating residents around a nuclear reactor in Fukushima prefecture.