North Korea fired seven ground-to-air missiles into the sea off its east coast on Thursday in an operation supervised by leader Kim Jong-un, the defence ministry in the South said, amid heightened tensions accompanying joint military exercises involving the US.

A ministry spokesman said Kim was understood to have been on hand when the missiles were fired early on Thursday evening from a site near the eastern town of Sondok.

The exercise came at a time of elevated tensions with North Korea’s condemnation of annual US-South Korea military drills that Pyongyang views as rehearsals for invasion. The North Korean regime has also signed a

“We see this as another show of force by the North related to the exercises,” the spokesman told AFP.

One of the joint drills, Key Resolve, wound up on Friday but the other, Foal Eagle, is set to continue until 24 April.

The annual exercises always trigger a surge in military tensions between the two Koreas, who remain technically at war because the 1950-53 Korean conflict ended with a ceasefire rather than a peace treaty.

North Korea signalled its displeasure when this year’s drills began by firing two short-range ballistic missiles into the sea off its east coast.

UN resolutions ban any ballistic missile test by North Korea.