BEIRUT, Lebanon — A group of Syrian rebels took responsibility on Sunday for the kidnapping of 48 Iranians in Damascus a day earlier, but the rebels insisted that their captives were members of Iran’s elite Revolutionary Guards, not religious pilgrims as Iran’s official news agency had reported.

“They are Iranian thugs who were in Damascus for a field reconnaissance mission,” said a rebel leader, in a video that the rebels said showed the captives sitting calmly behind armed Syrian fighters. In the video, the rebels flipped through what they said were Iranian identification cards and certificates for carrying weapons, proving, the rebels said, that the hostages were not religious pilgrims.

The identities and motives of the captives could not be independently verified, and some rebel groups have not embraced the kidnapping or the theory laid out by the fighters in the video. Col. Malik al-Kurdi, a deputy commander of the Free Syrian Army — one of several competing umbrella groups involved in the fighting — said the brigade taking responsibility for the kidnapping appeared to have been acting on its own and did not tell the Free Syrian Army about the operation.

Iranian officials said the kidnapped Iranians were pilgrims, denying that any of them were members of the Revolutionary Guards, Iran’s Arabic-language channel Al Alam reported Sunday, quoting an unnamed government spokesman. On Saturday, Iran’s foreign minister, Ali Akbar Salehi, contacted the Syrian and Turkish foreign ministries, asking them to secure the release of the 48 Iranians.