The unification ministry said it will continue efforts to resume operations of the inter-Korean liaison office as it marked the third anniversary of the office, an official said Tuesday.

This year's anniversary comes as the North blew up the liaison office building in June last year in anger over the sending of anti-Pyongyang leaflets by activists in the South.

The North also remains unresponsive to calls from South Korea via liaison and military hotlines after they were restored late July following a yearlong severance.

"The government considers it unfortunate that the operations of the inter-Korean liaison office continue to remain suspended," a ministry official said.

"We will continue to make efforts for the restoration of the inter-Korean communication lines and the resumption of the liaison office," she said.

The official added that the North has not responded to the regular phone calls via the inter-Korean liaison office as of Tuesday morning.

The joint liaison office opened in the North's border city of Kaesong in September 2018 to support inter-Korean exchanges and cooperation after a summit agreement between South Korean President Moon Jae-in and North Korean leader Kim Jong-un in April that year. (Yonhap)