WASHINGTON (AP) -- Secretary of State Rex Tillerson says that North Korea has released Otto Warmbier, an American serving a 15-year prison term with hard labor for alleged anti-state acts on Tuesday.

Tillerson says that Warmbier is on his way back to the U.S. to be re-united with his family.

Warmbier's parents say he is on his way home but is in a coma.

Tillerson said in a statement that the State Department secured Warmbier's release at the direction of President Donald Trump. The State Department continues discussing three other detained Americans with North Korea.

Warmbier is a University of Virginia student from suburban Cincinnati. He was sentenced in March 2016 after a televised tearful public confession to trying to steal a propaganda banner.

The announcement of Warmbier's release comes as former NBA player Dennis Rodman is paying a return visit to North Korea.

Rodman says he hopes his trip will "open a door" for U.S. President Trump.

Rodman's arrival in Pyongyand on Tuesday was relatively low-key and his schedule remains a mystery.

His stay is expected to last until Saturday.