"It is necessary to negotiate a transition [of power] with the Syrian regime, but afterward Assad should leave," Reynders was quoted as saying by La Derniere Heure newspaper.
Syria has been mired in a civil war since 2011, with government forces loyal to the Syrian president fighting against numerous opposition factions and extremist groups, such as the Nusra Front and Islamic State, which are banned in a range of countries, including Russia.
The cessation of hostilities in Syria came into effect at midnight on February 27 Damascus time, after the United States and Russia reached an agreement earlier in February on a ceasefire between the Syrian government and opposition groups to help end the country’s civil war.
The West maintains that Assad has no place in Syria's future, while Moscow considers Assad to be legitimate authority in Syria and has said it is up to the Syrian people to decide on their future.