A large bloc supported by Qatar that left Syria's opposition National Coalition has reversed its decision and wants to rejoin, setting the scene for confrontation with the group's Saudi-backed president, opposition sources said on Sunday.
The 40 members, who withdrew from the 120-member coalition before Syrian peace talks began in Geneva in January, said they had returned to confront what they saw as their unfair exclusion from the decision making process.
Infighting within the opposition coalition has undermined rebel efforts to take on forces loyal to Syrian President Bashar al-Assad, and has also played into the hands of rival, more hardline militant outfits which include some foreigners.
U.S.-and Russian-sponsored talks in Geneva to end the three-year civil war have stalled after two rounds in which the coalition and Assad's representatives failed to make progress on substantive political issues.
Bickering within the coalition reflects the broader regional rivalry between Qatar on the one hand and Saudi Arabia and its allies on the other, who have been known to back different, rival rebel brigades.
Tensions rose last week when Saudi Arabia, the United Arab Emirates and Bahrain withdrew their ambassadors from Qatar in an unprecedented public split between Gulf Arab allies who have fallen out over the role of Islamists in a region in turmoil.
Within the National Coalition, Qatar's candidate for the leadership of the group - former Syrian Prime Minister Riyad Hijab - narrowly lost out in January to Ahmad Jarba, who enjoys Saudi Arabia's support.
Jarba comes up for re-election in July, and coalition sources said the bloc's decision to rejoin the opposition appeared to be aimed at curbing his powers.
"We have decided to resume our political activity in the coalition as a single bloc," the 40 former defectors said in a statement.
They cited "perilous changes the Syrian revolt is undergoing", an apparent reference to divisions within the broad range of rebel factions fighting Assad.
The bloc also said it expected the Geneva talks to fail and attacked Jarba's decision to dismiss General Selim Idriss, a commander in the Free Syrian Army (FSA) who opposition sources said had opened channels of communication with Qatar.
Coalition spokesman Monzer Akbik declined to comment on the decision of the 40 to rejoin the coalition.
Haitham al-Maleh, a veteran human rights campaigner who heads the coalition's legal committee, said the 40 were entitled to attend the coalition's next full meeting, which has been delayed but could be held in a few weeks' time in Cairo.
"I hope they will attend," Maleh said. "We are in the midst of a revolution. We are trying to prevent Syria from descending into catastrophe. This is not the time for competition over positions."
But a coalition official, who asked not to be named, warned that the bloc's return could reignite tensions.
"Jarba is now expected to alter the composition of the FSA members to his advantage and strengthen his control of the coalition. The 40 have returned to try to prevent his re-election when it comes up on July 4," the official said.
A pro-Jarba opposition source added: "I think Jarba would be making a mistake if he lets the 40 rejoin. He is being urged by his allies not to allow them back in."
The most influential among the block of 40 is Mostafa Sabbagh, a businessman who is Qatar's point man in the coalition, and Hijab, the most senior figure to defect from Assad's government since the revolt began.