North Korea, defiant in the face of international condemnation of its latest nuclear test, fired two short-range missiles off its east coast on Tuesday and accused the United States of plotting against its government.
South Korea's Yonhap news agency quoted a government source in Seoul as saying the North had test-fired one surface-to-air and one surface-to-ship missile off of its east coast. The missiles had a range of about 130km.
On Monday, the communist state tested a nuclear bomb, many times more powerful than its first in October 2006, and fired off three short-range missiles, earning condemnation from the United Nations Security Council and governments worldwide.
US president Barack Obama called North Korea's nuclear arms programme a threat to international security. He spoke with South Korean counterpart Lee Myung-bak and Japanese Prime Minister Taro Aso on Monday to assure them of American support.
South Korea said it would join a US-led initiative to intercept ships suspected of carrying weapons of mass destruction - an act Pyongyang has warned it would consider a declaration of war.
The UN Security Council condemned the nuclear test on Monday, saying North Korea's latest nuclear test was a "clear violation" of a resolution passed in 2006 after the country's first test.
The council said it would begin work immediately on a new legally binding resolution to punish North Korea.
It demanded that North Korea abide by two previous resolutions, which among other things banned further nuclear tests and called for a return to six-party talks aimed at eliminating its nuclear programme.
US remains hostile, says North Korea
North Korea argues it has no choice but to build a nuclear arsenal to protect itself in what it believes is a hostile world. The country has frequently said it needs a deterrent to prevent any attack.
On Tuesday North Korea said the US administration under Barack Obama remained hostile and it was fully prepared for any American attack.
"It is clear that nothing has changed in the US hostile policy against DPRK (North Korea) ... even under the new US administration," state news agency KCNA said in an article criticising recent American moves to relocate its fighter jets.
"Our army and people are fully ready for battle ... against any reckless US attempt for a pre-emptive attack."
The North also criticised South Korea and Japan for denouncing its latest nuclear test and said this could prevent Pyongyang from joining a consensus to launch global negotiations on curbing nuclear weapons.
Message must be sent, says McCully
New Zealand Prime Minister John Key says North Korea's latest nuclear test could represent a threat to regional security and is a negative, retrograde step.
Foreign Affairs Minister Murray McCully says the country seems intent on taking a "hard-nosed" approach to international condemnation over the test.
Mr McCully says although it is not clear what impact another UN resolution will have, it is important to continue to send a message to North Korea.
He said New Zealand condemned steps taken by North Korea recently, but would not be drawn on whether it would support further sanctions.
North Korea has been punished for years by international sanctions and is so poor it relies on aid to feed its 23 million people.
Since 2003 China, Japan, Russia, South Korea and the US have been negotiating to persuade the North to abandon its nuclear programmes in exchange for energy and security guarantees.
The negotiations led to an agreement signed in 2007, under which the North said it would dismantle its nuclear facilities. The deal bogged down last December over ways to verify the North's declared nuclear activities.
In April this year, the North fired a long-range rocket for what it called a satellite launch, but which many nations believed was a disguised ballistic missile test. The rocket was fired over Japan and landed in the Pacific Ocean.
The UN Security Council condemned the launch and tightened sanctions, but a defiant North vowed to conduct a second nuclear test unless the world body apologised, announced it was quitting the six-way talks and said it would restart its plutonium-making programme.