China has increased radiation monitoring in its northeast following North Korea's nuclear test this week and found no immediate abnormalities, the Environment Ministry said on Thursday.

North Korea conducted its third nuclear test on Tuesday in defiance of U.N. resolutions, drawing condemnation from around the world, including from China which for years has been the North's only major ally.

Japan Meteorological Agency's earthquake and tsunami observations division director Akira Nagai points to a spot on the map showing the quake centre during a news conference in Tokyo February 12, 2013. Seismic activities detected at around 0300 GMT in North Korea may be the result of a nuclear test, Japan's top government spokesman said on Tuesday.

China would release radiation data twice a day from the northeastern provinces of Jilin and Liaoning, which border North Korea, the ministry said.

None of more than 150 radiation monitoring stations across China had reported abnormalities as of Wednesday, it added.

China last ramped up its radiation monitoring in 2011 after an earthquake and tsunami destroyed Japan's Fukushima nuclear power plant, triggering fuel-rod meltdowns and radiation leakage in the world's worst nuclear crisis since Chernobyl in 1986.                                                  TTO