BEIJING (Yonhap) ― A former U.S. ambassador to South Korea said Friday that he called on North Korea to swiftly release detained American Kenneth Bae during this week’s visit to Pyongyang and expressed “regret” over the North’s cancellation of a U.S. envoy’s visit aimed at securing his release.

Donald Gregg, who served as U.S. ambassador to Seoul from 1989-1993 and made a five-day trip to North Korea as head of a U.S. private institute, said he conveyed his call for Bae’s freedom to the North Korean side.

“When we heard that he was not going to be released, I expressed regret and said that I hope he would be released soon,” Donald Gregg said.

Bae, 45, has been detained in North Korea for more than a year after being sentenced to 15 years of hard labor on charges of attempting to overthrow the regime.