Istanbul (CNN) — A prisoner exchange involving thousands of Syrian and Turkish captives and at least 48 Iranians was under way Wednesday in Damascus, Syria, according to a Turkish charity organization that has been involved in previous prisoner swaps in Syria.
The Syrian government was releasing 2,130 civilians, including 73 women, in exchange for the release of 48 Iranian prisoners held by Syrian rebels, said Bulent Yildirim, president of the Humanitarian Relief Foundation in Turkey, according to the semi-official Turkish Anatolian Agency.
Iran has backed Syria during the nearly two year war which has pitted Syrian rebels -- many just average citizens in the country -- against the regime of President Bashar al-Assad. The rebels, known generally as the Free Syrian Army, want Assad gone, they say, because that will lead to greater freedom in Syria.
Iran's semi-official news agency FARS published a story Wednesday saying that 48 Iranian pilgrims who had been "abducted by terrorists in Syria in August have been released."
Al-Assad has routinely referred to Syrian rebels as terrorists.
A spokesman for the Syria rebels hailed the prisoner exchange as a victory for their cause, and said it may be the biggest prisoner exchange the rebels have conducted with their Syrian government adversaries.
The timing of the prisoner exchange is also notable as it happened after a fiery speech al-Assad gave just this past Sunday in which he vowed to continue to push back against the rebels. The prisoner exchange appears to contradict that assertion.
"It's a huge victory for us. It's a huge victory for the revolution. And it's a huge victory for the Syrian people," said Louai al Miqdad, a political and media coordinator for the Free Syrian Army.
Al Miqdad has been to two previous exchange negotiations and he said he felt this latest one was bigger.
"What we do today is a big victory for the Free Syrian Army," he said. "It shows the whole world that Bashar al-Assad only understands the language of force. Today, we released them by our hand."
Huseyin Oruc, deputy president of the Humanitarian Relief Foundation, spoke to CNN by phone.
The prisoners "are being handed over right now. We have teams on the ground in Damascus. They are at various police stations handling the exchange," he said.
"We also have a team handling the handover of the 48 Iranians from the opposition."
According to the charity, the swap is the result of three months of negotiations.
The freed Syrian and Turkish captives include about 80 women and children, he said.
Among them are four women civilians known as the "bride activists," Miqdad said. Rima al Dali, Kinda Azzaour, Lubna Azzaour and Roua Azzaffar were arrested wearing wedding dresses two months ago as they protested violence in their country.
Some of the Syrian and Turkish prisoners were held in the main prison in Damascus, and others in a prison run by the intelligence branch, Miqdad said.
He said the Iranian prisoners being released were members of a group abducted by rebels in Damascus last August.
The Iranian government denied rebel claims that the 48 captives were members of Iran's Revolutionary Guard. Tehran says the 48 Iranians were Shiite pilgrims visiting a holy site in the Syrian capital.
Opposition leaders accused the Syrian government of placing the freedom of several dozen captives from its ally Iran above the release of thousands of Syrian loyalist soldiers believed to be in rebel custody.
"One Iranian person means more to him (al-Assad) than a thousand soldiers," Miqdad said. "The command came direct from Tehran."
"The big prize for the regime is the Iranians, keeping them happy," said George Sabra, vice president of the National Coalition of Syrian Revolutionary and Opposition Forces. "The regime never cared about the lives of the civilian population or even his own armed forces."
Iranian state-run media reported that "foreign-backed militants in Syria have released 48 Iranian pilgrims." Like Syria, Iran refers to Syrian rebels as foreign-backed militants or terrorists.
Iran's state-run SANA news agency reported that "Iran hoped that permanent, comprehensive security and stability return to Syria" and quoted the Iranian Foreign Ministry had characterized the prisoner exchange as a release of Iranians who had been abducted in Syria.
It stressed the necessity of respecting the human rights' principles declared in the international agreements which ban attacking the innocents, considering the abduction of the visitors as contradictory to the human principles.
Syrian state-run media has not yet reported on the prisoner exchange.
Meanwhile, as the Syrian war grinds on with no end in sight, the United Nations said Wednesday that Lakhdar Brahimi, the U.N.-Arab League envoy to Syria, would meet Friday with Russian Deputy Foreign Minister Mikhail Bogdanov and U.S. Deputy Secretary of State William Burns.
The meeting in Geneva, Switzerland, is "aimed at furthering their discussions to arrive at a political solution to the crisis in Syria," a spokesman for U.N. Secretary-General Ban Ki-moon said.
But on the ground, blood kept flowing.
A car bomb rocked the Damascus suburb of Modamieyah on Wednesday, with reports of deaths and injuries, according to the Syrian Observatory for Human Rights, an activist group.
Fighting also continued in the Taftanaz area of northern Syria, where rebels are engaged in a fierce battle for a key Syrian air base.
Al-Nusra Front, a militant group that the United States has designated as a terrorist movement, is among three rebel factions attacking the base in Idlib province, rebels have said.
Elsewhere, wintry weather appeared to put a brake on some military operations.