Syrian rebels on Wednesday freed 48 Iranians held captive since August in exchange for the release of more than 2,000 detainees in the first major prisoner swap of the country's civil war, officials said.
The exchange came just days after Assad vowed to press ahead with the fight against rebels despite international pressure to end the bloodshed that has left more than 60,000 people dead.
Iran is one of Assad's main backers and the Iranians, who were seized outside Damascus in August, were a major bargaining chip for factions trying to bring down his regime.
The group of 48 men arrived at the Sheraton hotel in several vans escorted by Syrian security forces. Iran's ambassador in Damascus, Mohammad Riza Shibani, greeted them with hugs and flowers.
Rebels claimed the captives were linked to Iran's powerful Revolutionary Guard, but Tehran has denied that, saying the men were pilgrims visiting Shiite religious sites in Syria.
Shibani said their release was a result of elaborate and "tough" negotiations, but he did not provide any other details of the deal. The Syrian government, which rarely gives details on security related matters, had no official comment and it was not clear what prompted the exchange.
The rebels had threatened to kill the captives unless the Syrian regime halted military operations against the opposition.