South Korean civic groups and citizens expressed grave concern over the nuclear test by North Korea on Tuesday, urging the Seoul government to deal more sternly with the communist neighbor.

"North Korea should be held responsible for bringing about extreme tension in Northeast Asia," Kim Sam-soo, an official at the Citizens' Coalition for Economic Justice, said.

Kim also stressed that the incoming Seoul government should continuously urge Pyongyang to abide by all U.N. Security Council resolutions and keep its denuclearization pledge with the international community.

"(North Korea's) security policy relying on nuclear weapons would only bring about more nuclear threats," said Lee Tae-ho, a secretary general of the leading Seoul-based civic group, Peoples' Solidarity for Participatory Democracy.

"North Korea should break away from the thought that a nuclear deterrent would protect its regime," Lee noted.

The Korea Freedom Federation also denounced the test, saying that it is a provocative act that disregards the ongoing peaceful efforts by neighboring countries.

"The (South Korean) government should firmly punish (North

Korea) by cooperating with the international community," the Seoul-based conservative organization said in a statement.

Other Seoul citizens have shown concern and at the same time reprimanded the Seoul government for its lax response to North Korea's provocations.

"This nuclear test is the result of the current administration being too soft on North Korea," a 31-year-old Seoul man said.

"The international community, including the U.N. Security Council, does not deal strongly with North Korea's provocative acts because our government does not deal sternly with them," he said, voicing concerns over Seoul's policy.

"I think the lack of communication between the two Koreas eventually resulted in this worrisome situation," a 30-year-old Seoul woman said, noting that Seoul should at the same time have a flexible response.

Many South Korean Internet users have also voiced concerns over the test and urged the local authorities to step up their security measures.

"I hope that the South Korean government will firmly deal (with the test) by coming up with strong sanctions against North Korea," a Seoul resident tweeted.

"It would be more realistic to say that (the Seoul government) failed to properly handle North Korea due to botched diplomacy and administration," another Twitter user said, rebuking the test as "provocative." (Yonhap News)