North Korea fired multiple unidentified cruise missiles on Tuesday into the sea off its west coast, South Korea's military said, the third time Pyongyang has tested cruise missiles in less than a week.
The missiles were launched at around 7:00 am (2200 GMT on Monday), Joint Chiefs of Staff said in a statement.
South Korean and US intelligence authorities were closely monitoring the situation and analysing the details of the launch, it said.
The launch comes amid a rise in tension on the Korean peninsula and follows a barrage of cruise missiles fired by Pyongyang off its east coast on Sunday.
Sunday's launch was a test of the new submarine-launched cruise missiles (SLCM) dubbed "Pulhwasal-3-31" and leader Kim Jong Un supervised the test, North Korean state media KCNA reported on Monday.
Last week's missiles were also Pulhwasal-3-31, KCNA said, adding that they were "strategic", which typically refers to nuclear-capable weapons.
South Korea's JCS said last week it believes the firing of "Pulhwasal-3-31" was to test upgrades of existing missiles' capabilities.

Trump adds seven countries to full travel ban list
Indian parliament votes to allow private firms in nuclear power sector
Doctors in England start five-day walkout during flu surge
Israeli settler kills 16-year-old Palestinian in West Bank, mayor says
Paris' Louvre reopens partially but staff vote to extend strike
Delhi restricts vehicles, office attendance in bid to curb pollution
India summons Bangladesh envoy over security concerns in Dhaka
Alleged Bondi gunman charged with 15 murders as funerals of victims begin
