North Korea launched on Friday a ballistic missile that travelled 800 km before falling into the East Sea, South Korean military said

The launch comes just days after leader Kim Jong-un said his military had successfully tested nuclear warhead re-entry and that it will soon test ballistic missiles that can carry nuclear warhead.

The missile, which was fired around 5:55 a.m. from the western area of Sukchun, is believed to be a Rodong missile, the Yonhap news agency said, citing the Joint Chiefs of Staff (JCS) of South Korea's military.

North Korea had launched two short-range missiles into the East Sea last week, remonstrating the joint military exercise between South Korea and the US.

The firing of a ballistic missile is the latest act of provocation from Pyongyang, which is on a collision course with the US over its nuclear and ballistic missile programmes.

The UN imposed this month the toughest ever sanctions on North Korea after the nuclear rogue regime conducted it fourth nuclear test in January, followed up with a string of suspected missile tests.

Friday's missile launch was conducted from an area near the west coast north of the capital, Reuters reported. It flew across the peninsula and into the sea off the east coast early in the morning.

Acts of provocation from North Korea are routine at times of heightened military tension with its rivals.

Earlier this week, leader Kim Jong-Un declared his country successfully tested a simulated nuclear warhead re-entry and that it will soon test launch ballistic missiles that can carry nuclear warhead.

The atmospheric re-entry test of a ballistic missile that measured the "thermodynamic structural stability of newly-developed heat-resisting materials" proved the reliability of the inter-continental ballistic missile (ICBM) warhead re-entry, Kim said, according to KCNA.

The reclusive kingdom has also said it has developed miniaturised nuclear warheads and that it was prepared to launch pre-emptive nuclear strike on the US.