At a time of heightened tensions on the Korean Peninsula, North Korean authorities have proposed direct inter-Korean contact.

According to a Seoul official Saturday, a North Korean agency in charge of managing the jointly operated Gaeseong Industrial Complex told its South Korean counterpart Thursday that Seoul government officials should visit Gaeseong on April 21st.

The North said it plans to notify the South of a matter of grave importance during the meeting.

The government official said it remains uncertain whether the matter is about a South Korean worker detained in Gaeseong by the North or the management of the industrial zone.

Unification Minister Hyun In-taek presided over a meeting Saturday to discuss the dispatch of South Korean representatives to Gaeseong in response to the meeting invite.

A South Korean worker has been detained by the North for 20 days for allegedly denouncing the Pyongyang regime.

The North’s meeting notification comes at a time when South Korea has announced its imminent participation in the U.S.-led Proliferation Security Initiative. Pyongyang has said that Seoul’s participation in the anti-proliferation program would be considered a declaration of war.