North Korea launches missiles into eastern waters, according to the South

US State Department urges Kim Jong-Un's reclusive government to 'exercise restraint'

South Koreans watch TV news showing a footage of North Korean missiles (AP)

North Korea has launched three missiles into the sea off its east coast, reheating simmering tensions and prompting mild rebukes from the US and UK.

A South Korean official told Reuters: "North Korea fired short-range guided missiles twice in the morning and once in the afternoon off its east coast," an official at the South Korean Defence Ministry spokesman's office said by telephone.

"In case of any provocation, the ministry will keep monitoring the situation and remain on alert."

The firing comes weeks after tension subsided on the peninsula. The North had issued regular threats of aggression, at one point suggesting a "nuclear war" might be imminent.

In March, the reclusive state said it had entered a "state of war" with South Korea. Analysts doubted the credibility of the threats, saying they were aimed at drawing Washington into talks that could result in aid and boosting leader Kim Jong-un's image at home.

A Japanese government source noted the new launches, but said none of the missiles had landed in Japan's territorial waters, the Kyodo news agency reported.

The United States declined to comment directly on the reported launches but said it was monitoring the situation.

The State Department and the Pentagon said in a statement: "We continue to urge North Korea to exercise restraint and take steps to improve its relations with its neighbours."

Britain's Foreign Office said: "We have been clear to North Korea that its long-term interests will not be served by threatening the international community and increasing regional tensions."

Last December the North conducted a successful launch of a long-range missile, saying it had put a weather satellite into orbit. The United States and its allies denounced the launch as a test of technology that could one day deliver a nuclear warhead.

North Korea last launched short-range missiles in February and March. Such tests do not draw as much attention as the North’s longer-range ballistic missiles, which the country is barred from launching under UN resolutions.