SEOUL (AFP) - North Korea on Monday (March 21) fired five short-range rockets or missiles into the sea off its east coast, just days after test-firing two medium-range missiles in defiance of UN sanctions, South Korea's military said.

An official with South Korea's Joint Chiefs of Staff said the five short-range missiles were launched from near the eastern city of Hamhung, beginning just before 3:20pm (0620 GMT), and landed in the East Sea (Sea of Japan).

He said analysts were still gathering intelligence on the precise missile type.

Military tensions have been soaring on the divided Korean peninsula since the North carried out its fourth nuclear test on January 6, followed a month later by a long-range rocket launch that was widely seen as a disguised ballistic missile test.

The UN Security Council responded earlier this month by imposing its toughest sanctions on North Korea to date.

In recent weeks, Pyongyang has maintained a daily barrage of nuclear strike threats against both Seoul and Washington, ostensibly over ongoing, large-scale South Korea-US military drills that the North sees as provocative rehearsals for invasion.

Last Friday, the North test-fired two medium range missiles in line with an order from leader Kim Jong-Un to prepare a series of missile launches as well as a nuclear warhead explosion test.

The UN Security Council condemned the launches as "unacceptable" and a clear violation of existing UN resolutions.

North Korea often fires missiles during periods of tension on the Korean peninsula. On 10 March, it also fired two short-range missiles into the sea off its east coast, in a show of force against ongoing US-South Korea military exercises. It also declared all cross-border economic agreements with South Korea null and void.

This story is developing.