UNITED NATIONS - NORTH Korea will 'pay a price' if it continues to carry out nuclear weapon and missile tests in violation of international law, US ambassador to the United Nations Susan Rice said on Tuesday.

'If you want to continue to test and provoke the international community, they're going to find they'll pay a price because the international community is clear: it's not acceptable,' Dr Rice said on CNN television, in reaction to Pyongyang test-firing two short-range missiles Tuesday.

The tough words from Washington came a day after the UN Security Council unanimously condemned North Korea for testing a nuclear bomb Monday, as major powers mulled fresh punitive action and US President Barack Obama pledged support to Pyongyang's neighbors.

'You heard the entire international community yesterday from various capitals and from the security council come out swiftly, forcefully, and in unity to condemn' the tests, Dr Rice said.

'We agreed yesterday we're going to pursue in the security council a new resolution - a strong resolution with teeth,' she said, adding that sanctions 'could take very different forms' and might include 'economic levers'.

After Monday's emergency meeting at UN headquarters in New York, member states decided to 'immediately' begin working on a new Security Council resolution to address the weapons tests, council president Vitaly Churkin of Russia said, declaring 'strong opposition and condemnation of the nuclear test' by the body.

The Security Council said Monday's nuclear and missile tests violated UN Resolution 1718 adopted in October 2006 after North Korea's first atomic test.

The resolution forbids the reclusive regime from conducting any future nuclear tests or missile launches. -- AFP