Seoul: North Korea test-fired short-range missiles on Monday, South Korean media reported, sparking consternation just as the reclusive state had been signalling to the outside world it might return to nuclear talks.

US Secretary of State Hillary Clinton, reacting to the reported launches, said Washington would continue to work towards a nuclear-free Korean peninsula, while a Russian official expressed bewilderment.

South Korea's Yonhap news agency quoted a government source as saying Pyongyang had launched five missiles off its east coast and declared a "no sail" zone in the area from October 10-20.

South Korean government officials were not immediately available for comment and North Korean state media, by late evening, had made no reference to any incident.

The latest launches, the first in about three months, come as Pyongyang has said it is ready to return to international talks on its nuclear weapons programme, though it has insisted it holds talks first with the United States.

A South Korea military official said that if the report was true, it was a surprise but could not say if the firings were a provocation because "they do it pretty often."

But they coincided with local media reports that the United States is planning to send its aircraft carrier USS George Washington to the South Korean port of Busan today.

Clinton, speaking at a news conference in Belfast, said the United States and its allies were trying to demonstrate to North Korea that the international community would not accept its continuing nuclear programme.

"Our goals remain the same. We intend to work toward a nuclear-free Korean peninsula," she said.

Russia was more forthright in its criticism of the North.

"The launch of short-range missiles by the Korean People's Democratic Republic causes bewilderment," Itar-Tass news agency quoted a Russian Foreign Ministry source as saying.

Country's firepower

The Arsenal: North Korea has well over 1,000 missiles of various ranges. It has sold missiles and missile technology overseas, with Iran being one of the large buyers. The North has more than 800 ballistic missiles — including 600 Scud missiles of various types and 200 Rodong missiles.

Short-range: North Korea has hundreds of non-ballistic missiles with ranges of 150km or less. These include surface-to-air and surface-to-ship missiles.

Scud Type: These include the Hwasong-5, with a range of about 300km and the Hwasong-6, with a range of about 500km.

Rodong Type: The Rodong has an estimated range of 1,000 to 1,400 km. It can hit all of South Korea and most of Japan.

IRBM: North Korea recently deployed a new type of mid-range ballistic missile that can travel about 3,000 km. The unnamed intermediate range ballistic missile (IRBM) has a range that puts US military bases in Guam at risk.