Seoul: North Korea fired four short-range projectiles towards the sea Wednesday in the latest of a series of missile, rocket and artillery tests, the South`s defence ministry said.
The latest launches began at 07:30am (2230 GMT) at a site near Mount Myohyang, northeast of Pyongyang, with two fired in the morning and another two in the afternoon, all towards the Sea of Japan (East Sea), the ministry said.
"The type of the projectiles is not known," a ministry spokesman told AFP.
"The test of two projectiles lanched in the morning appeared to be unsuccessful because they just flew for several seconds, while two other projectiles fired in the afternoon travelled for up to 210 kilometres (126 miles)," he said.
The ministry declined to confirm a Yonhap news agency report that the North might have tested new 300-millimetre multiple rocket launchers.
The exercise came as cross-border military tensions run high following a series of missile, rocket and artillery launches in recent weeks.
North Korean leader Kim Jong-Un guided a missile-firing drill last Saturday after the United Nations Security Council condemned Pyongyang for its recent ballistic missile tests in violation of UN resolutions.
The North`s state media described Saturday`s short-range missile test as a "rocket-firing drill" to simulate a strike on military bases in South Korea where 28,500 US troops are stationed.
The North often fires missiles and rockets as a show of force or to express anger at perceived provocations, but the frequency of the recent tests is unusual.
UN resolutions bar North Korea from conducting any launches using ballistic missile technology.
But the North has defended the missile launches as a response to "madcap war manoeuvres" by the US.
Pyongyang has been playing hawk and dove in recent weeks, mixing its tests with peace gestures that have been largely dismissed by Seoul.
The two Koreas are currently trying to sort out logistics for the North`s participation in the Asian Games, which begin in September in the South Korean city of Incheon.