North Korea has reportedly tested seven surface-to-air missiles off its East coast, amid escalating tensions on the Korean Peninsula in the wake of ongoing US-South Korea military exercises.

The South Korean Joint Chiefs of Staff (JCS) said in a statement that the North Korean military ‘fired multiple rounds of ground-to-air missiles into the East Sea from Seondok, South Hamkyong Province’, at around 6pm to 7pm.

A South Korean military official was quoted by Reuters as saying: "We believe they test-fired different kinds of surface-to-air missiles and the longest range is about 200km (125 miles).

"We believe they test-fired different kinds of surface-to-air missiles."

"It appears Kim Jong-Un observed the firing."

The missiles are believed to be SA-2 or SA-3s, and one SA-5 medium-to-high-altitude surface-to-air missile, which has a range of 200km, BBC News reported.

The US and South Korea recently completed the first of two large-scale annual military exercises, code-named Key Resolve. It was designed to ensure that the alliance is prepared to defend South Korea.

North Korea also launched two short-range missiles into the East Sea in an apparent response to the start of the exercises earlier this month, calling them a provocation and prelude to an invasion.

However, the US maintains that the drills are aimed at enhancing operational readiness.

The second joint and combined field training exercise, Foal Eagle, features 200,000 South Korean and 3,700 US soldiers, and is scheduled to continue until 24 April.