North Korea fired two short-range missiles on Monday (May 20), making six launches in three days, and it condemned South Korea for criticising what it calls legitimate military drills.
South Korea's Defense Ministry said North Korea had fired one missile on Monday morning and a second one in the afternoon.
Both were fired into the sea off North Korea's east coast, a ministry official said.
The launches come hard on the heels of more than two months of threats from North Korea that it would wage a nuclear war against South Korea and the United States if it were attacked.
The North condemned joint U.S. and South Korean military exercises, that ended in late April, as a rehearsal for an attack on its territory.
North Korea frequently fires short-range missiles, although the current spate of launches has drawn criticism from South Korea and the United States after the recent threats from the North.
There appears to be little prospect of talks between North Korea and the United States as Washington insists that Pyongyang needs to abandon its nuclear weapons programme, something the isolated and impoverished state has said it will not do.
Presented by Adam Justice