PARIS (Reuters) - A proposed summit on Oct. 19 between Russia, Ukraine, France and Germany to discuss the conflict in Ukraine can only take place if there is "real progress" on the key stumbling blocks in the coming days, a French diplomatic source said on Tuesday.

"There has to be real progress between now and then, and the leaders need to agree, so we can't confirm it will happen," the source said when asked if there would be a meeting in Berlin next week.

(Reporting By Elizabeth Pineau; Writing by John Irish; Editing by Ingrid Melander)