The head of a Turkish aid agency that helped broker the prisoner exchange has confirmed that 48 Iranian hostages have been freed in exchange for the release of more than 2,000 civilians.
Bulent Yildirim, head of humanitarian aid agency IHH, told Reuters that the exchange was underway: "The 48 Iranians have been released and are being taken to Damascus, accompanied by Iranian and Syrian officials."
CNN's Arwa Damon says it is the biggest prisoner swap since the uprising began.....
Reaction to prisoner swap
Initial reaction to news of the prisoner swap has focused on how much more highly the Assad regime appears to value Iranians compared to imprisoned Syrian activists.
Rafif Jouejati, spokeswoman for the activist group the Local Co-ordination Committees of Syria, tweeted: