BERLIN (Reuters) - Despite all their differences, opposition groups in Syria agree that there cannot be a future with Syrian President Bashar al-Assad, German Foreign Minister Frank-Walter Steinmeier told a conference hosted by his Social Democrat party on Tuesday.

Steinmeier repeated his call for an end to the bombardment of civilians in the Syrian city of Aleppo and other parts of the country, and said a transition plan was needed to get to a political solution for ending the civil war there.

He said there were discussions about bringing humanitarian relief supplies into Aleppo via Turkey, but there were no guarantees for success.

(Reporting by Andreas Rinke; Writing by Andrea Shalal; Editing by Madeline Chambers)