North Korea is to liquidate all South Korean assets on its territory following the imposition of the latest round of sanctions by Seoul, Pyongyang said Thursday.
All treaties on economic cooperation would be treated as invalid, the South Korean news agency Yonhap reported, citing a statement by North Korea.
Everything that belongs to South Korean firms in the country would be sold, it said.
In reaction to the latest North Korean atomic test in January and a controversial rocket launch in February, Seoul on Tuesday blacklisted 38 North Koreans and 24 organisations connected with Pyongyang's nuclear programme.
This bans them from financial transactions with South Korean banks.
In February, South Korea closed the Kaesong industrial park run jointly with Pyongyang, just over the border in North Korea.
Tensions have been rising in the region since Pyongyang's latest atomic test.
North Korea's military fired two short-range rockets towards the open sea on Thursday.
The missile tests were seen as a response to ongoing military manoeuvres by the South Korean armed forces with the US military.
The launches prompted Japan to hold a National Security Council meeting, in which Prime Minister Shinzo Abe demanded that North Korea not conduct further provocations and vowed to respond firmly against Pyongyang in close coordination with the international community, Kyodo News agency reported.