The Syrian National Coalition, an umbrella opposition group, called Tuesday for a transitional government under UN auspices to end the country's civil war, dpa reported.
President Bashir al-Assad needs to "account for" the bloodshed, Syria's main opposition organization said after two days of talks in Madrid.
The opposition was seeking a common position to present at a conference in Geneva, which has been proposed by Russia and the United States although no date has been set, opposition representatives said earlier.
Spanish Foreign Minister Jose Manuel Garcia-Margallo was scheduled to meet Ahmed Moaz al-Khatib, who resigned last week as leader of the Syrian National Coalition, citing weak international support for the opposition.