Beijing, Sep 10 (IANS): China said radiation levels in the country were normal and neither the environment nor the health of its citizens was affected so far by the fifth nuclear test conducted by North Korea.

China's Ministry of Environmental Protection on Friday activated its contingency plan to monitor a possible increase in radiation levels along its northeastern border after seismic activity was detected in North Korea.

However, initial analysis revealed no irregularities, EFE news reported citing state media as saying on Saturday.

North Korea conducted its fifth nuclear test on Friday that culminated with Pyongyang's 68th anniversary.

The test, the second one in eight months, was carried out at the Punggye-ri Nuclear Test Site, located less than 100 km from North Korea's border with China.

The proximity of the test site from the border of China gave rise to concerns about the nuclear fallout from the explosion.

The Environmental Protection ministry has said it will closely monitor radiation levels in the area and make the results public.

The test provoked strong criticism from the international community, including China, who firmly opposed it and summoned the North Korean ambassador in Beijing.

Bilateral ties between the two countries have cooled in recent times, especially after repeated nuclear and missile tests, which led the UN Security Council to impose tough sanctions against Pyongyang in March, the toughest in 20-years.