Heavy fighting between Syrian rebels and troops sent thousands fleeing across the border into Turkey on Friday, as President Bashar al-Assad said his future could only be decided at the ballot box.
The clashes over a border post near the northeastern town of Ras al-Ain killed 46 combatants in two days, a watchdog said, and highlighted the humanitarian crisis and regional dangers posed by Syria's nearly 20-month conflict.
The United Nations said more than 11,000 Syrians had fled into neighbouring countries in the previous 24 hours alone, including 9,000 into Turkey, bringing to more than 408,000 the number of registered Syrian refugees in the region.
The UN said the total number of Syrian refugees in Turkey, Lebanon, Jordan and Iraq would likely hit 700,000, and the head of its humanitarian efforts said those in need of emergency aid in Syria would rise to more than four million early next year.
"This will just continue to grow in the terms of humanitarian suffering," John Ging, who heads the UN's Office for the Coordination of Humanitarian Affairs, or OCHA, told reporters in Geneva.
At least 20 Syrian soldiers were killed in Friday's clashes over the Ras al-Ain post, one of only two crossings on the Turkish border still in regime hands, the Syrian Observatory for Human Rights said.
It said rebels had captured numerous soldiers and taken control of key positions in mainly Kurdish Ras al-Ain, including the offices of the security and intelligence services.
Turkish officials said 8,000 refugees had fled the fighting in Ras al-Ain overnight and that most were taken to a camp in Akcakale near the border.
In an interview with Russian television, meanwhile, Assad said that whether the president can "stay or leave" is a "popular issue" and "the only way (it) can be done (is) through the ballot boxes."
Assad warned Syria was facing a protracted conflict because foreign powers were backing rebels fighting his regime, but insisted there was no civil war.
He admitted divisions existed in the country, but said "division does not mean civil war," and denied his forces had committed war crimes.
State-backed Russia Today had on Thursday released excerpts of the interview in which Assad vowed to "live in Syria and die in Syria" and warned that foreign intervention would have global consequences.
A car bomb outside a mayor's office in the town of Muadamiya al-Sham south of Damascus killed four civilians on Friday, the Observatory said, while at least 12 civilians were killed in shelling in the eastern province of Deir Ezzor.
On Friday at least 114 people were killed nationwide, including 53 soldiers and 47 civilians, it said.
-- 'Bashar, you will die in Syria' --
Thousands of protesters rallied on Friday, with many mocking Assad's "live and die" remarks.
"Bashar, you will die in Syria, but you won't be buried in the ground, you will be thrown in the dustbin of history!" read one sign held by protesters in the central city of Hama.
Assad's foes in the opposition met in the Qatari capital Doha, meanwhile, for Western- and Arab-backed efforts to unite in a government-in-waiting representing the whole spectrum of regime opponents.
Participants in the talks said most delegates had agreed on a unified opposition structure that would allow coordinated military action, as well as humanitarian aid and the administration of zones under rebel control.
But representatives of the main exiled opposition group, the Syrian National Council, voiced reservations over the proposal tabled by prominent dissident Riad Seif with apparent US support.
The SNC asked for a delay until late Friday to give its decision, allowing itself time to first elect a president.
On the ground, the rebel Free Syrian Army said it was reorganising and relocating its leadership to rebel-held territory in a bid to win vital international support.
General Mustafa Sheikh, who heads the FSA military council, told AFP in northern Syria that the group had started to restructure itself into five divisions -- north, south, east and west, and the coast -- and would elect new leaders.
"We are getting closer and closer to becoming organised, so that we can get to a stage that is accepted by the international community," he said.
Sheikh said the FSA leadership, based largely in neighbouring Turkey, is countering criticism from its rank and file by relocating around 200 officers -- including himself -- back to "liberated" parts of Syria.
The Observatory says more than 37,000 people have died since the uprising against Assad erupted in March 2011, first as a protest movement and then an armed rebellion after the regime cracked down on demonstrations.