Seoul, Jan 19 (IANS): South Korean President Park Geun-hye on Tuesday said he was worried about sending a wrong signal to North Korea unless strong UN sanctions are imposed on Pyongyang over its fourth nuclear test.

Park said in a cabinet meeting that if strong and effective measures were not drawn up, it would give a wrong signal to North Korea that the international society can do nothing over Pyongyang's fifth and sixth nuclear tests, Xinhua reported.

The president urged officials to make diplomatic efforts to draw up strong and comprehensive sanctions from the UN Security Council by closely cooperating with allies.

Tensions rose on the Korean peninsula after North Korea claimed on January 6 that it tested its first hydrogen bomb.

South Korea resumed blaring propaganda messages from loudspeakers across the border into North Korea, which in turn, restarted its own propaganda broadcasts in response.

Pyongyang scattered over one million copies of anti-South Korea leaflets through air balloons in part of Seoul and some of the northern region close to the inter-Korean border.

Park said the military should maintain solid defence readiness over Pyongyang's possible provocations, noting that the military should immediately retaliate against any North Korea provocation.

She instructed the military to make a thorough preparation for possible cyber attack from North Korea.

A large amount of emails impersonating the South Korean presidential office and the foreign ministry had been reportedly sent to Seoul government officials to poll opinions about Pyongyang's fourth nuclear test.

The impersonated emails were believed to have been sent from Pyongyang to conduct a cyber attack. The South Korean policy had launched an investigation.