WASHINGTON — The State Department says North Korea has rescinded its invitation for a senior U.S. envoy to travel to Pyongyang to seek the release of a detained American.

Bob King, the U.S. special envoy for North Korean human rights, was due to travel today from Tokyo to Pyongyang to request a pardon and amnesty for Kenneth Bae.

Bae has been sentenced to 15 years of hard labor by the authoritarian state, accused of subversion.

Department spokeswoman Marie Harf said the U.S. is “surprised and disappointed by North Korea’s decision” and remains gravely concerned about Bae’s health.

King intends to return to Washington from Tokyo on Saturday.

This is a further setback to U.S.-North Korean relations, already strained by concerns over Pyongyang’s nuclear program.