BEIRUT: The Syrian opposition chief Ahmed Moaz al-Khatib has announced his resignation from the National Coalition, throwing Syria's divided opposition into disarray ahead of an Arab summit.

"I announce my resignation from the National Coalition, so that I can work with a freedom that cannot possibly be had in an official institution," Mr Khatib said in a statement posted on his Facebook page on Sunday.

Neither the Coalition's presidential office nor its general assembly has yet accepted Mr Khatib's resignation, the group said in a statement.

"Some coalition members have asked Khatib to return to his post," an opposition source told AFP, adding the group had yet to decide whether to accept Mr Khatib's decision.