Sohae launch site, North Korea
The ballistic missile launch has been confirmed by the US and South Korea Kyodo/Reuters

North Korea has fired a ballistic missile into the sea off the east coast of the Korean peninsula, just days after the UN imposed fresh sanctions on the country, South Korea has said. South Korean officials said that a missile was fired near Sukchon county, South Pyongan province and flew a distance of 800km (500 miles).

Fired from an area north of Pyongyang on the west coast, it was said to have travelled across the peninsula and landed in the Sea of Japan. The launch comes amid fierce rhetoric coming from the isolated nation and the UN Security Council imposing sanctions earlier in March after a January missile test by the North.

Seoul said they were closely tracking and monitoring the developing situation and maintaining a "readiness for provocation" from the Democratic People's Republic of Korea (DPRK). They did not confirm the type of missile fired, but South Korean media said it was believed to be a medium-range Rodong missile.

Only last week the hermit nation fired two short-range missiles into the Sea of Japan with Kim Jong-un ordering more nuclear weapons tests. The nation is known to fire missiles when tensions are high.

Recently China, the US and Japan have all put on pressure on North Korea to abandon its weapons programme. But Kim believes that the nation has a right to develop the missiles and warned this week that, if needed, they will conduct a "pre-emptive and offensive nuclear strike" in response to joint exercises by US and South Korean troops near their borders.

The new sanctions – issued on 16 March – included the blacklisting of individuals and entities that deal with the DPRK's economy. This was in reaction to the nation's fourth nuclear test on 6 January.

Only a week ago, North Korea fired two missiles from North Hwanghae province, south of Pyongyang, toward the sea east of the Korean Peninsula.