S Arabia warns Qatar against backing Syrian opposition

Qatar has ruffled feathers of the GCC after a large Qatar-backed bloc that had left the Syrian opposition, reversed its decision and decided to rejoin the US-backed National Coalition fighting the Bashar al-Assad regime.

Qatar's decision has set the scene for a clash with the group's Saudi-backed president, opposition sources said on Sunday.

An angry Saudi Arabia threatened to blockade neighbouring Qatar by land and sea unless it cuts ties with the Muslim Brotherhood, closes Al Jazeera, and expels local branches of two US think tanks - the Brookings Doha Centre and the Rand Qatar Policy Institute.

At a meeting of GCC foreign ministers in Riyadh last week, Saudi foreign minister Saud bin Faisal is reported to have said only these acts would be sufficient if Qatar wanted to avoid "being punished."

The 40-member bloc backed by Qatar had earlier quit the 120-member opposition coalition before Syrian peace talks began in Geneva in January.

But the block has now changed its mind and said it had returned to confront its unfair exclusion from the decision-making process.

With growing infighting within the opposition coalition hardline Islamist outfits, which include foreign militants, have started gaining upper hand within the Syrian opposition alliance, threatening the stability of other Arab countries as well.

The Saudi rulers are both enraged and threatened by the role that Qatar-based Al Jazeera played in the first years of the Arab Spring, which saw the deposing of Tunisian and Egyptian governments. Al Jazeera is now giving sympathetic coverage to the Syrian opposition and the Egyptian Islamists.

Three journalists from Al Jazeera, its Egypt bureau chief Mohamed Fahmy,  Australia correspondent Peter Greste and Egyptian producer Baher Mohamed appeared in court in Cairo last week accused of "joining a terrorist group, aiding a terrorist group, and endangering national security." A fourth journalist, from Al Jazeera Arabic, Abdullah al-Shami is being tried in a separate case.

The Saudi demand for shutting down the Brookings and Rand Corporation policy advisors in Doha will embarrass US president Barack Obama, who is due to visit Riyadh at the end of month.

US secretary of commerce Penny Pritzker who was in Abu Dhabi on Sunday, had sought closer economic cooperation between the United Arab Emirates, Saudi Arabia and Qatar with Washington to broaden and deepen security ties.

US- and Russian-sponsored talks to end the three-year-old civil war in Syria have stalled after two rounds in which the opposition coalition and Assad's representatives failed to make substantive progress.