Yemeni girls shout slogans during a demonstration demanding the resignation of Yemeni President Ali Abdullah Saleh, in Sanaa, Yemen, Saturday, 9 April 2011. (AP)
Yemeni President Ali Abdullah Saleh initially accepted an offer by Saudi Arabia and other Gulf Arab states including Qatar, as part of the Gulf Cooperation Council (GCC), to hold talks with opposition parties after two months of protests against his 32-year-long rule.
But on Friday, Saleh reacted angrily to comments from Qatar's prime minister and foreign minister saying the mediation would lead to Saleh standing down.
"We don't get our legitimacy from Qatar or from anyone else ... We reject this belligerent intervention," Saleh told tens of thousands of supporters in the capital. On Saturday Yemen said it would withdraw its ambassador from Doha.
Sunday's meeting in Riyadh will evaluate the official response of Saleh and Yemen's opposition coalition, after Yemen's foreign minister said on Saturday that Saleh was still open to the Gulf mediation, which Yemen views as Saudi-led.
"He has announced personally that the Yemeni government is studying the Gulf initiative and has not declared any rejection of it," Foreign Minister Abubakr al-Qirbi was quoted as saying on Yemen's official Saba news agency.
The Qatari comments "gave the impression that the issue had already been resolved". Qatar is home to leading pan-Arab broadcaster Al Jazeera, whose Yemen correspondents have had their licences revoked for what Sanaa calls bias.
Saleh has sought Saudi mediation for some weeks, but analysts say both Saudi Arabia and United States are now keen to arrange a quick exit for a man they had viewed as an ally in the fight against al Qaeda.
Diplomats and opposition sources say he is manoeuvring to ensure that he and his sons do not face prosecution, the fate of the deposed rulers of Tunisia and Egypt, and the Saudi mediation could give him that guarantee.
Saleh, a veteran political operator, has warned of civil war and the breakup of Yemen if he is forced to leave power before organising new parliamentary and presidential elections over the next year or is not sure of who succeeds him. He has seen a string of generals, diplomats and tribal chiefs announce their opposition to him but has organised large public displays of support in recent weeks.
The killing of more than 100 protesters by security forces has begun to convince countries of the region that Saleh is now an obstacle to stability in a country that sits on a shipping lane carrying more than 3 million barrels of oil a day.
Some 40 percent of Yemen's 23 million people live on less than $2 a day and one-third face chronic hunger. Exasperation with state repression and rampant corruption have added further fuel to the pro-democracy movement.
Even before the protests Saleh was struggling to quell a separatist rebellion in the south and a Shi'ite insurgency in the north, violence that has given al Qaeda militants more room to operate.
Violent clashes have continued almost daily over the past week, with at least 27 people killed, as security forces use live ammunition and tear gas.