MOSCOW, Aug 20 (Reuters) - German Chancellor Angela Merkel urged Russian President Vladimir Putin after talks in Moscow on Friday to release Kremlin critic Alexei Navalny and to extend a gas transit deal with Ukraine that expires in 2024. "I have demanded once again from the president to release Navalny and I have made it clear that we will remain on the case," Merkel said. "We also spoke about the transit deal with Ukraine, which could and should be extended beyond 2024." Writing by Joseph Nasr; Editing by Maria Sheahan Our Standards: The Thomson Reuters Trust Principles.