SEOUL, Sept. 9 (Xinhua) — South Korean President Park Geun-hye strongly denounced the Democratic People's Republic of Korea (DPRK) 's fifth nuclear test during her overseas trip of Laos, her office said on Friday.

Park, who has stayed in the Laotian capital of Vientiane to attend the East Asia Summit (EAS), said that the DPRK conducted a second nuclear test this year following the January test, strongly criticizing it as a clear violation of UN Security Council resolutions and a grave challenge to the international society.

Her denunciation followed the DPRK's fifth nuclear test Friday morning at its main Punggye-ri test site. Seoul's military said artificial seismic waves were detected from a 5.3 magnitude quake close to Punggye-ri, where the fourth nuclear detonation was carried out in January.

South Korea regards the latest test as the most powerful as the 5.3 magnitude can put its estimated explosive yield at about 10 kilotons. Six kilotons of explosive yield were spotted from the fourth test.

The president said her government will push for additional harsher sanctions, both bilateral and multilateral in UN Security Council, in cooperation with the international society, vowing to strengthen pressures on Pyongyang with all available measures to make it give up its nuclear program.