North Korea fired suspected artillery pieces into the sea on Sunday, South Korea's military said, days after the North's latest missile launch ended in failure amid the country's recent burst of weapons testing activity.
There is speculation that North Korea could soon try to launch its developmental longest-range ballistic missile to bolster its arsenal and dial up pressure on the United States to wrest concessions as negotiations remain stalled.
South Korea's military suggested North Korea's midair missile explosion last Wednesday involved parts of the Hwasong-17 missile, its biggest weapon.
On Sunday, South Korea's Defense Ministry said it detected firings likely from multiple rocket launch systems off North Korea's west coast.
The ministry said the military closely monitors North Korean moves and maintains its readiness.
South Korea's presidential office said in a separate statement it held an emergency national security council meeting to discuss what it called the North's “short-range projectile launches.” Council members worked to analyse details of the firings in close coordination with the United States, it said.
The statement added that South Korea will use its enhanced military capability and its alliance with the U.S. to prevent a security vacuum from occurring during a power transition period in Seoul.
President Moon Jae-in's single five-year term ends in May and he will be replaced by a new conservative government led by Yoon Suk Yeol.
A former top prosecutor, Yoon has vowed to boost Seoul's military alliance with Washington and win a stronger U.S. security commitment to neutralise growing North Korean nuclear threats.
Wednesday's failed missile firing was the North's 10th weapons launch this year.
The U.S. and South Korean militaries said they concluded that two of North Korea's recent launches before Wednesday's were meant to test a Hwasong-17 system.
North Korea later said those launches were designed to test cameras and other systems for a spy satellite.
Some outside experts say North Korea will likely fire a Hwasong-17 rocket to test its long-range missile technology and also to put its first functioning spy satellite into orbit.
The Hwasong-17's potential maximum range of 15,000 kilometers would place the entire U.S. mainland within its striking distance, and its huge size suggests it can carry a bigger payload or multiple nuclear warheads.
The Hwasong-17 launch, if made, would be the North's most serious provocation since the country carried out three intercontinental ballistic missile tests in 2017.
The South Korean government didn't immediately disclose where Sunday's weapons firings occurred.
The Koreas' poorly marked western sea boundary saw naval clashes in 1999, 2002 and 2009.
Attacks blamed on North Korea in the area in 2010 killed 50 South Koreans — 46 on a warship and four on a border island.
