Rebel fighters said Sunday that 48 Iranians captured in the Syrian capital were not the pilgrims their government asserts but instead were affiliated with Iran’s elite Revolutionary Guard Corps, on a mission in Damascus to help the Syrian government crush the rebellion.

The allegation underlined the regional dimensions of the conflict, as rebels backed by pro-Western powers in the Middle East, including Turkey and Saudi Arabia, battle the regime of President Bashar al-Assad, backed by Russia and Iran, for control of towns and cities across the country.

In a video broadcast by the al-Arabiya television channel, a man identifying himself as a representative of the al-Baraa battalion of the rebel Free Syrian Army identified the 48 Iranians as “shabiha,” the word used to describe pro-government militias in Syria. He produced documents that he said proved that one of the men was an officer in the Revolutionary Guard with a permit allowing him to carry arms.

The Iranians were “on a reconnaissance mission in the field to study the situation in the city” when their bus was seized by rebels Saturday, the Free Syrian Army commander said. Several dozen men, apparently the captured Iranians, sat behind him as he spoke.

“We warn Iran and all those who stand with the regime: The fall of this regime is inevitable,” the rebel commander said. “We pledge that the fate of all who work on your behalf in the land of Syria will either be imprisonment or death.”

If confirmed, the capture would seem to support long-standing rebel claims that Iranians have been helping Syrian security forces with their crackdown on the nearly 17-month-old uprising. U.S. officials have accused Iran of providing materiel, intelligence and training to help crush the rebellion.

Iran’s official Islamic Republic News Agency reported that the Iranians were pilgrims on a visit to the Shiite shrine of Sayeda Zeinab, in a southern suburb of Damascus, when their bus was intercepted by rebels. The news agency said Iran had asked Turkey and Qatar, which wield influence over the Free Syrian Army, to secure the men’s release.

The abduction, in an outlying neighborhood that has long drawn Shiite tourists because of the shrine, pointed to the continued rebel presence in the capital despite government claims that its forces quelled an opposition offensive in the city last month.

At the same time, Syria made clear that it blames Turkey and the Arab countries of the Persian Gulf for recent rebel advances. The official Syrian Arab News Agency said government forces were pursuing “Gulf and Turkish terrorist militias” in the city of Aleppo, an apparent reference to recent news reports that Turkey and the gulf countries were helping arm the rebels.

The State Department announced that Secretary of State Hillary Rodham Clinton would visit Turkey on Saturday for consultations on the Syrian crisis.

The Britain-based Syrian Observatory for Human Rights said at least 40 people were killed in violence nationwide Sunday, including 10 army soldiers and five rebels.

Ahmed Ramadan in Beirut contributed to this report.