The 47-year-old currently has a deal with Dortmund that runs until 2018. Klopp extended his contract in 2013 after arriving at the Westfalenstadion in 2008, per the Press Association (h/t The Guardian).
Belgian journalist Kristoff Terreur passed on the report from German newspaper Bild:
Bild reports: Jurgen Klopp has asked to terminate his contract with Borussia Dortmund. http://t.co/dQVXu57dYc
— Kristof Terreur (@HLNinEngeland) April 15, 2015
Klopp has had great success at Dortmund during his tenure, winning Bundesliga titles in 2011 and 2012 and leading his side to the Champions League final in 2013, where they lost to Bayern Munich.