The mainstream Syrian rebel command distanced itself from the jihadist Al-Nusra Front on Tuesday after Al-Qaeda in neighbouring Iraq confirmed that it spawned and supervised the group.
The Free Syrian Army insisted that alliances it has struck with Al-Nusra fighters on the ground were only tactical, local and time-limited, as Al-Qaeda openly admitted the Iraq links of one of the spearheads of the armed uprising against the Damascus regime.
"We don't support the ideology of Al-Nusra," FSA spokesman Louay Meqdad told AFP.
"There has never been and there will never be a decision at the command level to coordinate with Al-Nusra. The situation on the ground is what has imposed this."
Washington already blacklisted Al-Nusra as a terrorist organisation earlier this year citing its close links to Al-Qaeda fighters who led the insurgency against US forces in Iraq before their withdrawal last year.
But the head of Al-Qaeda's front group in Iraq, Abu Bakr al-Baghdadi, confirmed on Tuesday that Al-Nusra was its creation and that its leader Abu Mohammed al-Jawlani was "one of our soldiers".
"It is time to declare to the Levant and to the world that the Al-Nusra Front is simply a branch of the Islamic State of Iraq," Baghdadi said in an audio message posted on jihadist forums.
He said the groups would merge under the banner of the Islamic State in Iraq and the Levant.
Some Syrian rebel commanders have acknowledged discomfort at Al-Nusra's jihadist ideology, its resort to suicide bombings against civilians and its use of foreign recruits.
But the group has also won respect as a disciplined and effective fighting force in the battle to overthrow President Bashar al-Assad's regime, winning key territory from his troops.
"Al-Nusra exists, it is financed and it is armed. That's why certain brigades of the FSA cooperate with them on certain operations on the ground," the mainstream rebel spokesman said.
"It's a tactical and time-limited cooperation... Al-Nusra is not attached to the FSA," Meqdad added.
Al-Nusra has said it is seeking an Islamic state in Syria after Assad's overthrow, but Meqdad insisted: "No one has the right to impose on Syrians what shape their state will take.
"Syrians will go to the polls to choose their leaders," he said. "Our goal is clear -- to bring down the regime and establish a democratic state."