"Statements from both sides confirmed there's a big divide," Brahimi, the special U.N.-Arab League envoy to Syria, told reporters in Montreux, Switzerland, at the end of an acrimonious first day of ministerial speeches before talks aimed at ending Syria's nearly 3-year-old civil war start Friday.
"We will be meeting with them [Thursday], separately, and we will discuss what the next steps will be," the veteran Algerian diplomat who is mediating between the sides said after Syrian Foreign Minister Walid al-Muallem defiantly called Syrian insurgents evil and ignored U.N. Secretary-General Ban Ki-moon's appeal to avoid epithets.
Muallem refused to yield the floor when Ban signaled he exceeded his allotted 8 minutes.
"You live in New York, I live in Syria," Muallem snapped. "I have the right to give the Syrian version here in this forum. After three years of suffering, this is my right."
"Let me finish my speech," he said angrily. Ban let him go on.
Muallem's remarks lasted more than 30 minutes.
Brahimi told reporters he might need more time to discuss the terms of Friday's talks before bringing the two sides into the same room.
Those direct negotiations, planned for nearby Geneva, would be the first direct talks between the regime of President Bashar Assad and opposition forces since Syrian unrest began March 15, 2011.
The official objective of the peace talks, known as Geneva II, is to establish a process to create a transitional government with full executive powers.
The transitional government would run the country until elections could be held that likely wouldn't include Assad.
This was the objective worked out at an international conference on the Syria conflict, known as Geneva I, held in Geneva in June 2012.
Syria has said its intention for the talks is to fight "terrorism." The regime uses that term to describe the armed opposition.
"We have come here to put an end to terrorism and its bitter consequences," Muallem told delegates from more than 30 nations. "Diplomacy and terrorism cannot go in parallel. Diplomacy must succeed by fighting terrorism."
Syrian National Coalition President Ahmad al-Jarba said Syrians "waited almost a year before they fought back," referring to the transformation of a largely peaceful protest movement to an armed insurgency.
"Who, ladies and gentlemen, would accept to be violated in this manner? How long should they have waited?"
He said photos showing the Assad regime's alleged torture of detainees were "unprecedented except in the Nazi camps during the second world war."
Jarba said the opposition would never accept a role for Assad in a transitional administration.
Assad has also said he would not step down or share power with the opposition.
U.S. Secretary of State John Kerry said in his remarks Assad must go.
"There is no way ... that the man who led the brutal response to his own people could regain the legitimacy to govern," Kerry said.
Muallem responded, "No one, Mr. Kerry, has the right to provide legitimacy ... except for the Syrian people."
Brahimi told reporters that despite the initial hostility, "We have had some fairly clear indications that the parties are willing to discuss issues of access to needy people, the liberation of prisoners and local cease-fires."
Kerry separately said Washington and Moscow sought to find other ways of pressing for a resolution to the crisis.
"There are still other possibilities of ways to be able to bring pressure and to try to work a solution," he said.
Kerry said he and Russian Foreign Minister Sergei Lavrov spoke about these options at the mutual request of President Barack Obama and Russian President Vladimir Putin, who Kerry said "talked at some length about this."
"I can tell you this," Kerry said. "What you see in the direct talks between the opposition and the Assad regime will not be the full measure of effort being expended in order to try to find a solution here."
He added, "Lots of avenues will be pursued, including continued support to the opposition and augmented support to the opposition."