Syrian Observatory for Human Rights said after the beheading earlier this week, the victim was determined to be an anti-government fighter injured in clashes against the Syrian Army, CNN reported Thursday.
An online statement Thursday from a spokesman for the al-Qaida-affiliated Islamic State of Iraq and the Levant, whose fighters apparently carried out the beheading of Mohammed Fares, sought forgiveness for the executioners and asked for "restraint and piety" from anti-government supporters.
"We call on God to accept Mohammed Fares into his kingdom and to forgive his brothers that sought to rid us of the enemies of God and our enemies," Omar al-Qahatani said in the online video statement.
Fares apparently called out names of two revered figures in Shiite Islam while hospitalized, prompting the Sunni opposition to assume he was a government fighter, al-Qahatani said.
In a separate online video, two of the group's fighters are seen holding what appears to be a head and telling a crowd he was an "Iraqi Shiite volunteer fighter in Bashar Assad's army."
CNN said human rights groups and some members of the Syrian opposition have condemned what they consider horrendous actions by the radical group, including alleged executions of wounded government soldiers, the shooting of a 15-year-old boy for blasphemy and public floggings of women for acts determined to violate Sharia law.
Washington and Moscow have targeted Dec. 12 as the date when they hope long-stalled peace talks on Syria's civil war will be held, a Syrian newspaper reported.
The U.S. State Department and Russian Foreign Ministry did not confirm the date, reported by Syrian Arabic-language newspaper al-Watan, owned by a cousin of Assad.
The newspaper, citing Western diplomats in Paris, said U.N. Secretary-General Ban Ki-moon was expected to make the peace-talks announcement Nov. 25.
The report came the same day Syria said it would send envoys to Moscow Monday to discuss the so-called Geneva II talks in the Swiss city.
That announcement followed a Kremlin statement that Russian President Vladimir Putin spoke with Assad Thursday about the peace talks and the destruction of Syria's chemical stockpile.
It was the two leaders' first phone conversation in more than two years, the Kremlin said.
Putin, who initiated the call, "underscored the efforts by Russia and its partners to prepare for the Geneva II international conference and gave a positive assessment to Bashar Assad's readiness to send a Syrian government delegation to this event," the Kremlin said in a statement.
"The hope was expressed that the main opposition groups will show a constructive approach and take part in the conference," the statement said.
Moscow, a strong Syrian ally, blames Syria's main exile opposition group, which Washington supports, for paralyzing diplomatic efforts to end the civil war with its insistence Assad step down as a precondition for any talks.
Washington, Moscow, the United Nations and the Arab League have sought to hold international peace talks since early this year. But intended dates kept getting postponed, from March to June to July and, most recently, to Nov. 24.
State Department spokeswoman Jen Psaki told reporters she could not confirm the Dec. 12 date.
The Assad regime has said it is ready to take part but Assad's removal will not be considered.The exile opposition Syrian National Council has repeatedly said it was willing to join the talks only if Assad had no role in Syria's governance.