BERLIN, June 3 (Reuters) - A window for dialogue is slowly opening between Russia and Europe on Ukraine, although it is likely to be months before talks can begin, a German government official said at a briefing on Wednesday.
The official, who asked not to be named, said it was essential to establish an effective format for dialogue that the Europeans perceive as legitimate.
It was also unclear who would lead such talks, although the official said there are strong indications the E3 Group - Germany, France and Britain - will continue to play an important role in that regard.
Advances by Russian forces have slowed this year, and Ukrainian troops are increasing pressure on the battlefield and through an intensified campaign of long-range strikes inside Russia, including on St Petersburg on Wednesday ahead of President Vladimir Putin's annual economic forum.
Ukrainian President Volodymyr Zelenskiy's chief of staff has said that agreeing a deal to end the war by winter was a "realistic" outcome.
The German official said recent fighting indicates it is likely to take months, rather than weeks, to reach a point where talks could begin, and that it was key to ensure they were conducted in full agreement with Ukraine.
Coordination - instead of competition - with the United States, whose brokered talks have stalled as Washington focuses on Iran, must also remain a guiding principle, said the official, as should close teamwork with the Europeans.
Germany and European governments have rejected a suggestion by Putin that former German chancellor Gerhard Schroeder could represent them in possible future talks with Moscow.
(Reporting by Andreas Rinke, Writing by Miranda Murray, Editing by Madeline Chambers and Sharon Singleton)
