The involvement of the Quds Force in Syria could be particularly worrying to Assad's foes. The unit is tasked with carrying out overseas operations for the Revolutionary Guards, and the U.S. military frequently accused it of training and arming Shiite militias in Iraq during the peak of the sectarian conflict there. In particular, the Quds Force was accused of supplying militia groups in Iraq with explosively formed penetrators, or EFPs. The deadly bombs, which can cut through thick armor, killed many American and Iraqi soldiers.
The Syrian government, for its part, has tried to focus the attention of the international community on the regional countries helping the rebels. Syrian officials on Sunday lashed out at the role Turkey is playing in the conflict by claiming that the Turkish government had opened its airports and borders to "al-Qaida terrorists" who have killed many Syrians and damaged public and private property in the country. The Syrian foreign ministry sent a letter of protest to the chairman of the U.N. Security Council and the U.N. secretary-general, the official Syrian Arab News Agency (SANA) reported.
On Friday, Pope Benedict XVI, while en route to Lebanon for a three-day visit, also criticized the regional dimensions of the conflict by saying that importing arms into Syria is a "grave sin." He again addressed the bloody conflict in Syria, which has left more than 25,000 dead according to opposition groups, during a Sunday Mass that drew tens of thousands of people in Beirut. "Why so much horror? Why so many dead?" he asked.
The rebel fighters have said they are receiving arms from Qatar and Saudi Arabia, although officials from those countries have said little about their role. Iran, Hezbollah and Turkey have all strongly denied accusations of sending arms.
In the news conference Sunday, Jafari said that defending Syria is a "point of pride" for Iran but he stopped short of promising military intervention if Syria is attacked. If that happened, Jafari said, Iran wouldn't necessarily invoke the bilateral security agreement between the two countries and respond immediately with military force. Iran's actions would depend on "conditions," he said, according to Fars News, without giving further details.
In late August, Gen. Salar Abnoush, the commander of the Revolutionary Guard's Saheb al Amr unit, said that Iran was involved in the Syria conflict without explicitly mentioning the presence of Iranian military personnel, according to Iran's Daneshjoo news agency.
But there have been hints of Iran's increased involvement in recent weeks. In early August, 48 Iranians were kidnapped from a bus in Damascus. The Iranian government claimed they were pilgrims but members of the Free Syrian Army, who carried out the kidnapping, claimed they were Revolutionary Guards and posted a video online in which some of the kidnapped Iranians showed what appeared to be Guard IDs.
Not long after, Iran's foreign minister Ali Akbar Salehi said there were some retired Guards and other retired military personnel among the group of kidnapped men but they had all traveled to Syria as pilgrims.
Iran's Revolutionary Guards are not only present in Syria. Jafari said Sunday that members of Iran's Quds Force are also in Lebanon in a non-military capacity without giving further details, according to Fars News.
Hezbollah, the Syrian government's strongest regional ally after Iran, has also been accused of sending fighters and weapons into the country. Asked about the role of Hezbollah in the Syrian conflict, Jafari did not rule it out.
"Syrian forces have come to the aid of Lebanon in the past, and it's natural that if Syria needs help that the people of Lebanon will go to help them," Jafari said, according to Fars News. "This will not be related to Iran and, with attention to their close ties in the past, it's not unlikely that this would happen."
In the news conference Sunday, Jafari also commented on the militia groups, often referred to as "shabiha" by the opposition, which have been fighting alongside the Syrian military. Opposition activists accuse the shabiha of carrying out some of the worst atrocities in the 19-month conflict.
Jafari compared these fighters to the Basij, a plainclothes militia under the command of the Revolutionary Guard in Iran, and claimed they are a potent force that aids the Syrian military.
"There are more than 50,000 Syrian people who have organized as a people's army, or a force of Syrian Basij, who are standing beside the army in the face of the unfair attacks from the countries of the region and outside the region," Jafari said.
The Syrian government carried out attacks in more than half a dozen cities across the country on Sunday, killing at least 113 people, according to the Local Coordination Committees, an activist network. More than 40 people were killed in Aleppo alone, many of them from heavy shelling, the group claimed.