Istanbul (CNN) -- Thousands of mostly Syrian prisoners were exchanged Wednesday for a few dozen Iranians in Damascus, a Turkish charity said.
The Syrian government released 2,130 civilians, 76 of them women, in exchange for the release of 48 Iranians who had been held by Syrian rebels, said Huseyin Oruc, deputy president of the Humanitarian Relief Foundation in Turkey.
Iran has backed the Syria government during the nearly two-year war that has pitted rebels against the regime of President Bashar al-Assad.
Iran's semi-official news agency FARS reported Wednesday that the released Iranians were pilgrims who had been "abducted by terrorists in Syria in August."
Al-Assad and Iran routinely refer to Syrian rebels as foreign-backed militants or terrorists.
The exchange took place after a speech delivered Sunday by al-Assad in which he vowed to continue to push back against the rebels.
"It's a huge victory for us," said Louai al Miqdad, a political and media coordinator for the Free Syrian Army. It's a huge victory for the revolution. And it's a huge victory for the Syrian people."
He added, "It shows the whole world that Bashar al-Assad only understands the language of force. Today, we released them by our hand."
Oruc told CNN in a telephone interview that four Turkish nationals and one Palestinian were also released by the Syrian government as part of the deal.
The foundation's teams in Damascus handled the exchange, which took place at various police stations, he said.
By late Wednesday, the freed Iranians were in Damascus and the freed Syrians had returned to their homes, he said.
According to the charity, the swap is the result of three months of negotiations.
Among the freed Syrians and Turks were four "bride activists," women who were wearing their wedding dresses when they were arrested protesting violence in their country, Miqdad said.
Some of the Syrian and Turkish prisoners had been held in the capital's main prison, and others in a prison run by the intelligence branch, Miqdad said.
He said the released Iranians were members of a group abducted last August by rebels in Damascus.
The Iranian government denied rebel claims that the freed Iranians were members of Iran's Revolutionary Guard. Tehran says they are Shiite pilgrims who were in Syria visiting a holy site in Damascus when they were abducted by "foreign-backed militants."
Opposition leaders accused al-Assad of valuing the freedom of a few dozen Iranians above the release of thousands of Syrian loyalist soldiers believed to be in rebel custody.
"One Iranian person means more to him 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."
Syria's state-run SANA news agency reported that "Iran hoped that permanent, comprehensive security and stability return to Syria" and said the Iranian Foreign Ministry had characterized the exchange as a release of Iranians who had been abducted in Syria.
It urged respecting principles declared in international agreements that ban the attacking of innocents and consider the abductions as contradictory to the principles of human rights.
Meanwhile, as the Syrian war ground on, 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, to be held in Geneva, Switzerland, would be "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, said the Syrian Observatory for Human Rights, an activist group.
Fighting also continued in the Taftanaz area of northern Syria, where rebels were engaged in a 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.
CNN's Saad Abedine, Salma Abdelaziz and Laura Smith-Spark contributed to this report.