North Korea said Friday it test-launched new anti-aircraft missiles, as its military threatened unspecified grave steps against the U.S. and South Korea over their joint military drills that it views as an invasion rehearsal.

Kim Jong Un oversees test-firing of North Korea’s latest anti-aircraft missile system - North Korea has already started the production of the anti-missile defence system and carried out the test to examine its performance,

North Korea has tested new missiles in response to joint military drills between the US and South Korea. The country has warned of strong actions if these drills continue, escalating tensions in the region.