"We direct the leadership of Al-Nusra Front to go ahead with what preserves the good of Islam and the Muslims, and protects the jihad of the Syrian people," Ahmed Hassan Abu al-Khayr said in an audio message released online by Al-Nusra.
"We urge them to take the appropriate steps towards this matter," said Abu al-Khayr, who was identified as a deputy of Al-Qaeda leader Ayman al-Zawahiri.
Al-Nusra's media arm, Al Manara Al-Bayda, also announced that the group's head, Abu Mohammad al-Jolani, was to deliver a speech and posted a picture showing him for the first time.
The image shows a smiling young man, with curly black hair and a beard, dressed in military fatigues and with a turban on his head.
Jihadist sympathisers and observers have been speculating online about a possible split between Al-Nusra and the network founded by Osama bin Laden to which it pledged allegiance in 2013.
Analysts say Al-Nusra aims to rebrand and defend itself as it comes under increased pressure after Moscow and Washington agreed to step up joint efforts against the group.
"Whatever Nusra does, its ultimate objective is to further embed itself into Syria's revolution and secure its long-term future" as a legitimate rebel group, analyst Charles Lister tweeted.
Al-Nusra first emerged in January 2012 -- 10 months after Syria's conflict began with anti-government protests that were brutally repressed by President Bashar al-Assad's regime.
It is Syria's preeminent jihadist group, along with its key rival, the Islamic State group.
But unlike IS, which opposes all those who fail to swear allegiance, Al-Nusra has worked alongside an array of rebel groups fighting Assad's regime and has popular support.
Al-Nusra is a key member of the Al-Qaeda network, alongside North Africa's Al-Qaeda in the Islamic Maghreb (AQIM) and Al-Qaeda in the Arabian Peninsula (AQAP), based in Yemen.
An image released on July 28, 2016 by Al-Manara al-Bayda, the official news arm of Al-Nusra Front, Al-Qaeda's Syrian affiliate, allegedly shows the group's chief Abu Mohammad al-Jolani at an undisclosed location, in the first ever picture to be released of him.
Al-Qaeda prepared the ground Thursday for a break with its Syrian affiliate, Al-Nusra Front, following several days of online chatter over a split between the jihadist groups.
