SEOUL, April 19 -- North Korea test-fired multiple ballistic missiles on Sunday, South Korea's military said, the latest in a recent flurry of launches by the nuclear-armed state.

The Sunday firing adds to a series of weapons tests Pyongyang has carried out in recent weeks.

"Our military detected several unidentified ballistic missiles fired into the East Sea from the Sinpo area of North Korea at around 06:10 (GMT 21:10)," the South's Joint Chiefs of Staff said, referring to a body of water also known as the Sea of Japan.

"We have strengthened surveillance and vigilance in preparation for possible additional launches," it added.

North Korea has tested weapons systems several times this month, including ballistic missiles and cluster m...