NHK is reporting that there was a hydrogen explosion at a nuclear reactor in northeastern Japan.

According to the report, the explosion was heard at around 11 a.m. at the number three reactor of the Fukushima Daiichi nuclear power plant in northeastern Japan's Fukushima Prefecture.

Following the explosion, smoke was seen rising from the reactor. The power plant lies 220 kilometers north of Tokyo.

Tokyo says there is little chance that dangerous levels of radioactive materials will be released due to the explosion.

This is the second explosion at a nuclear reactor in the area following the first one that occurred on Saturday.