North Korea has blown up a joint liaison office with the South near the North’s border town of Kaesong.
The move comes just hours after the North renewed threats of military action at the Korean border.
The site was opened in 2018 to help the Koreas – officially in a state of war – to communicate. It had been empty since January due to Covid-19 restrictions.
In a statement, South Korea warned it would “respond strongly” if the North “continues to worsen the situation”.
The destruction of the office, it said, “abandons the hopes of everyone who wanted the development of inter-Korean relations and peace settlement in the Korean Peninsula”.
“The government makes it clear that all responsibility of this situation lies in the North.”
Russia expressed concern at the renewed tensions between the Koreas.
“We call for restraint from all the sides,” Dmitry Peskov, a spokesman for President Vladimir Putin, said on Tuesday.
Reuters news agency quoted an unnamed senior US official as saying the Trump administration remained “in close co-ordination with our Republic of Korea (South Korea) allies”.
Tensions between North and South Korea have been escalating for weeks, prompted by defector groups in the South sending propaganda across the border.