United Nations Security Council members will be working closely on Tuesday to agree a resolution on North Korea, after unanimously condemning the country''s nuclear test explosion.

The Security Council held an emergency session on Monday, after the reclusive communist state announced an underground nuclear test blast, which Russia later said had a force similar to the bomb that destroyed Hiroshima.

After the talks, UN Ambassador Vitaly Churkin of Russia, which holds the council''s rotating presidency, said the members "voiced their strong opposition to and condemnation of the nuclear test."

"The members of the Security Council have decided to start work immediately on a Security Council resolution on this matter," he said.

Despite mounting international pressure, with some Western powers calling for sanctions, North Korea is reportedly planning new missile tests.

South Korea''s Yonhap agency quoted an intelligence source as saying the North has banned ships from the waters off its west coast, and is likely to launch anti-ship cruise missiles in the next two days.

North Korea reportedly test-fired a surface-to-air missile with a range of 80 miles (130 kilometers) from its northeastern Musudan-ri launch site on Monday, soon after the nuclear blast, which was confirmed by international seismic readings.

United Nations Secretary General Ban Ki-moon, a South Korean, issued a statement condemning the nuclear test, voicing concern that it could harm regional security and damage the non-proliferation regime, and calling for a unified position on the issue.

"The Secretary-General trusts that the Security Council will take up this matter to send out a strong and unified message, conducive to achieving the goal of de-nuclearization of the Korean peninsula and peace and security in the region," the UN said on its website.

"The Secretary-General reiterates his conviction that differences should be resolved in a peaceful manner through dialogue. He urges the DPRK to refrain from taking further actions that would increase tensions in the region," the statement said.