Former Pakistani Prime Minister Imran Khan's detention is arbitrary and in violation of international law, a U.N. human rights working group said in an opinion issued on Monday, adding the jailed politician should be immediately released.

The Geneva-based U.N. Working Group on Arbitrary Detention said that the "appropriate remedy would be to release Mr. Khan immediately and accord him an enforceable right to compensation and other reparations, in accordance with international law."

The U.N. working group said Khan's legal woes were part of a "much larger campaign of repression" against him and his Pakistan Tehree-e-Insaf party.