Syria’s opposition chief Ahmad Moaz al-Khatib has resigned from the National Coalition.

Syria's opposition chief Ahmad Moaz al-Khatib has resigned from the so-called "National Coalition," a dissident group recognized by dozens of states and organizations as a legitimate representative of the Syrian people.

"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," Khatib said in a statement published on Sunday on his Facebook page.

The surprise resignation comes just days after the first election in Istanbul of a rebel prime minister, Ghassan Hitto.

"Our message to all is that the Syrian people alone will take their decision. I had made a promise to our great people that I would resign if any red lines were crossed. Today, I am honoring my promise," Khatib said.

He had reportedly wanted to quit for some time, objecting to an interim premiership.