HEILIGENDAMM, June 8 (Reuters) - French President Nicolas Sarkozy said on Friday world leaders had failed to agree on the future of the Serbian province of Kosovo, whose Albanian majority are seeking independence in defiance of Belgrade. "There was no progress on Kosovo," Sarkozy told reporters at the end of a Group of Eight summit in Germany. Sarkozy had sought to persuade Russia, which backs Serbia's sovereignty over Kosovo, to agree to the region's eventual independence in exchange for a delay to a United Nations vote on the issue.