It is the first launch of a Nodong missile since 2009 and marks a step up from the short-range rockets Pyongyang has fired in recent weeks.

 

The launches also came on the fourth anniversary of the sinking of a South Korean warship. 

 

Washington and Seoul have condemned the launch, which violates UN resolutions. 

 

The US State Department described the launch as "a troubling and provocative escalation". 

 

"We urge North Korea to exercise restraint and refrain from further threatening actions," deputy spokeswoman Marie Harf said in a statement. 

 

'Grave provocation'

 

The South Korean defence ministry said the missiles were fired from the Suckon region north of Pyongyang and flew for about 650km before falling into the sea off the east coast of the Korean Peninsula.

 

"This missile is capable of hitting not only most of Japan but also Russia and China," ministry spokesman Kim Min-seok said. 

 

The ministry described it as a "grave provocation". 

 

In recent weeks, North Korea has launched multiple short-range missiles - actions which have coincided with annual US-South Korea military exercises.