BEIRUT: Syria's Al-Qaeda affiliate on Sunday set its conditions to stop battling the rival Islamic State of Iraq and Greater Syria, despite an order by the Al-Qaeda chief to quit fighting.
Al-Nusra Front and ISIS have in recent months fought intense, bloody battles against each other, particularly in eastern Syria on the border with Iraq.
"We will follow the orders of... Ayman al-Zawahiri... to stop any attack from our side against ISIS, while continuing to respond whenever they attack Muslims and all that is sacred to them," Al-Nusra said in a statement.
"As soon as ISIS announces the end of its attacks on Muslims, we will spontaneously stop firing," said the jihadist group, adding it had only fought ISIS in areas "where it was on the attack".
While rebels fighting to topple President Bashar al-Assad initially welcomed both Al-Nusra Front and later ISIS in the Syrian war, widespread opposition to ISIS later emerged over its quest for dominance in opposition-held areas.
Rebels including Islamists launched a massive offensive against ISIS on January 3, and Al-Nusra Front joined the fight against the group later on.
As far back as last June, Zawahiri weighed in on ISIS's involvement in Syria, designating Al-Nusra as responsible for operations there and ordering ISIS chief Abu Bakr al-Baghdadi to restrict the group's activities to its home base in Iraq.