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.
North Korean leader Kim Jong Un told Russia's top diplomat his country was ready to "unconditionally support" Moscow's every effort to resolve the conflict in Ukraine, state media reported on Sunday, as the two countries held high-level strategic talks.
A preliminary report depicted confusion in the cockpit shortly before an Air India jetliner crashed, killing 260 people last month, after the plane's engine fuel cutoff switches almost simultaneously flipped, starving the engines of fuel.
US President Donald Trump defended the state and federal response to deadly flash flooding in Texas on Friday as he visited the stricken Hill Country region, where at least 120 people, including dozens of children, perished a week ago.
Russia pounded Ukraine with hundreds of drones and dozens of missiles on Saturday, in the fourth major attack this month, targeting western cities and killing at least two people in Chernivtsi on the border with Romania.