A Syrian Islamist militant group has denied saying it was behind Thursday's bombings in the capital, Damascus.
The al-Nusra Front appeared to admit carrying out the attack - which killed 55 people - in a video which was posted on online on Saturday.
But on Tuesday, the group said it had not made the video, which it said was "fabricated", and "full of errors".
The group has claimed previous attacks, including a bombing in Damascus in mid-March that left 27 people dead.
The disputed video claimed al-Nusra had carried out Thursday's attacks, which targeted intelligence agencies, "in response to regime bombing of residential areas in Damascus, Idlib, Hama, Deraa provinces and others".
In common with many videos posted by activists and armed groups during the Syrian conflict, its authenticity was extremely difficult to verify.
The narrator's voice was digitally disguised, and the statement accompanying the film was entitled "Comminique Number 4", even though al-Nusra has previously posted seven such statements.
But a statement purportedly published by al-Nusra's media arm on jihadist forums on Tuesday said: "This video as well as the statement appearing in it are fabricated and... full of errors."
"We did not receive from the front's military department any affirmation or denial or information regarding the operation," it added. "Any further information arriving will be published on official jihadist forums."
The Russian foreign ministry said it believed al-Qaeda was behind the attack, while Syrian opposition groups said President Bashar al-Assad's government had carried it out in an attempt to discredit them.