North Korea has fired two short-range ballistic missiles into the sea, South Korea’s military has said.
It said the missiles, launched off the east coast, flew some 500km (310 miles) and fell into the water.
On Wednesday, North Korean leader Kim Jong-un claimed scientists had developed nuclear warheads small enough to fit on ballistic missiles.
The North has stepped up its bellicose rhetoric in response to the UN imposing some of its toughest sanctions.
The move by the UN Security Council came after the North conducted its fourth nuclear test in January and last month launched a satellite. Both actions contravened existing sanctions.
The two missiles were fired from Hwanghae Province on Thursday, the South Korean military said.
It added that the missiles later fell into the sea off North Korea’s east coast, without providing further details.
Pyongyang has so far made no public comment on the issue.
Last week, North Korea fired six rockets into the sea, using a multiple launch system.
The reported latest firing comes as US and South Korean forces are holding their largest ever round of annual military exercises.
The drills routinely generate tension, and Pyongyang has recently threatened to launch an “indiscriminate” nuclear strike on the US and South Korea.