The activists have sent leaflets and plastic bottles filled with rice across the border, prompting North Korea to raise provocations with the South.

North Korea abruptly used Park Sang-hak's leaflet campaign as a justification for a series of provocative steps against South Korea.

It was not immediately clear why North Korea had softened its position, which came after it blew up a liaison office last week and cut off communication hotlines with the South.

The move is certain to intensify tensions between the Koreas, after the North abruptly raised its rhetoric against South Korean civilian leafleting and pushed to resume its psychological warfare against the South.

South Korea now has 1,146 confirmed infections of the virus and 11 fatalities from the COVID-19 illness it causes.

Kim Dong-woo, an official from the fire department in the coastal city of Donghae, said the explosion occurred on the second floor of the motel where seven guests were using a gas stove to grill meat.