"I have decided to give a speech in the name of the Syrian people at the Doha conference,"  Moaz Al-Khatib, leader of the Syrian National Coalition wrote on his Twitter account. "This is a matter that has nothing to do with the resignation, which will be discussed later," he said.

The Arab summit takes place on Tuesday and Wednesday. Arab foreign ministers met in Doha on Sunday to prepare for the meeting. Al-Khatib did not say when he would speak.

Al-Khatib was picked as head of the coalition after it was formed in November. He was seen as a moderate bulwark against the rising influence of al Qaeda-linked forces fighting in the revolt against President Bashar al-Assad.

Al-Khatib did not give a full explanation for his decision to quit. In a statement on Sunday, he said he was resigning so he could work more freely.

He resigned after the coalition berated him for offering Assad a negotiated deal and after the group went ahead, despite his objections, with steps to form a provisional government that would have further diminished his authority.