(June 16): North Korea destroyed an inter-Korean liaison office on its side of the border Tuesday, South Korea said, shortly after threatening military action in the region over anti-Pyongyang leaflets sent into its territory.

The move was one of the largest provocations North Korea has made against its rival in years and comes after it has cut off communication links set up with its neighbour in 2018. “North Korea blew up the inter-Korean liaison office,” South Korea’s Unification Ministry said in a text message, confirming what many had begun to expect after media reports of an explosion in the area.

The destruction of the building comes about a week after Kim Jong Un’s regime abandoned its operations at the facility that once allowed the rivals to communicate around the clock. North Korea has in recent weeks issued an escalating series of threats against South Korean Moon Jae-in’s government in frustration over his continued support for the U.S.-led sanctions campaign against the country.

South Korean Unification Minister Kim Yeon-chul, who was at parliament in Seoul during the explosion, said the move was “expected.” South Korea needed to follow the situation more closely, he said, without elaborating.

Smoke and an explosion were observed rising from an area close to the industrial park in the North Korean border city of Kaesong on Tuesday, the Yonhap News Agency said. The industrial park was jointly established with South Korea, but has been shuttered amid tensions between the two rivals. The site is also home to a liaison office intended to maintain relations between Seoul and Pyongyang.

Cheong Seong-chang, director of the Centre for North Korean Studies at the Sejong Institute, said the latest action taken by North Korea illustrates its “strong will” to “completely shut off” its relations with the South.

“North Korea is working toward re-militarization of the Kaesong industrial complex,” Cheong said. “And blowing the liaison office in the complex would just be the first step on their road map.”

The liaison office was opened two years ago in the spirit of rapprochement advocated by Moon and was part of moves to reduce threats along the border, where the two countries have stationed about 1 million troops. It allowed for constant communication between the two sides for the first time since the start of the 1950-53 Korean War.

Chinese Foreign Ministry spokesman Zhao Lijian told a daily briefing after the incident that the country hoped for peace on the Korean Peninsula. He didn’t mention the liaison office. China is North Korea’s main benefactor and trade partner, and plays a key role implementing international sanctions against North Korea.

The one-month dollar-won non-deliverable forwards rose 0.4% to 1,212.36, implying the local currency will be weaker when onshore markets reopen on Wednesday.

“This probably isn’t enough to derail the broader risk rally today,” said Eddie Cheung, a strategist at Credit Agricole SA in Hong Kong. “But the geopolitical considerations around Korean assets are likely to rise a bit as this marks an active step (and not just a threat) toward cutting ties.”

Earlier Tuesday, North Korea said it was reviewing a plan to send troops into some areas of the Demilitarized Zone, but it didn’t specify what parts of the heavily fortified border it was considering entering. The statement appeared to be referring to a disarmed region near the office that was destroyed on the west side of the peninsula and a closed joint resort on the east around North Korea’s Mount Kumgang, the Yonhap News Agency reported.

Millions of leaflets have flown across the border for more than a decade bearing messages critical of North Korean leaders, with the latest coming as Kim made fewer public appearances over the past several weeks than normal, leading to global speculation about his health.