WASHINGTON: The United States is ready to intercept any North Korean long-range missile, a top US military commander said on Thursday, as Pyongyang further tested international patience with fresh launches.

"The nation has a very, very credible ballistic-missile defence capability," the commander of US Northern Command, General Victor Renuart, told The Washington Times.

"Our ground-based interceptors in Alaska and California ... give me a capability that if we really are threatened by a long-range ICBM (intercontinental ballistic missile) that I've got high confidence that I could interdict that flight before it caused huge damage to any US territory."

Washington has said it is not ruling out the possibility of a North Korean long-range missile launch toward Hawaii on or around July 4, the US Independence Day, although the Pentagon has expressed doubts about such a scenario.

But Renuart, commander of US NORTHCOM and the missile launch-monitoring US-Canada North American Aerospace Defence Command (NORAD), warned "we ought to assume there might be one... and continue to be prepared and ready."

His comments came as South Korean military officials said Pyongyang test-fired four short-range missiles Thursday, further fuelling tensions sparked by the North's nuclear standoff with the international community.

The launches were "not unexpected," said Bryan Whitman, a Pentagon spokesman.

"North Korea is looking for attention," added a US defence official who requested anonymity.

It was the first military action by the hardline communist state since the United Nations on June 12 imposed tougher sanctions for its May 25 nuclear test.

President Barack Obama had assured in late June that the United States is "fully prepared" for a potential North Korean missile launch toward US territory.

In addition to long-range interceptors in Alaska and California, the United States also has ground- and sea-based defence systems in the Asia Pacific, including ground-based Patriot anti-missile defences in South Korea, and US Navy Aegis system missile-defence ships deployed to waters close to Japan.

Thursday's North Korean missile launches came as a US delegation met Chinese officials in Beijing for talks on boosting UN sanctions imposed in June after the Stalinist state's May nuclear test. - AFP/de