MOSCOW -- The United Nations envoy for Syria warned on Saturday that the country's civil war could plunge the entire region into chaos by sending hundreds of thousands of refugees into neighbouring nations, but his talks in Moscow produced no sign of progress toward settling the crisis.

Lakhdar Brahimi and Russian Foreign Minister Sergey Lavrov both said after their meeting that the 21-month-old Syrian conflict can only be settled through talks, while admitting that the parties in the conflict have shown no desire for compromise. Neither official hinted at a possible solution that would persuade the Syrian government and the opposition to agree to a ceasefire and sit down for talks about a political transition.

Brahimi, who arrived in Moscow on a one-day trip following his talks in Damascus with Syrian President Bashar Assad this week, voiced concern about the escalation of the conflict, which he said is becoming "more and more sectarian."

The envoy warned that "if you have a panic in Damascus and if you have 1 million people leaving Damascus in a panic, they can go to only two places -- Lebanon and Jordan," and those countries may not be able to endure half a million refugees each.

Brahimi said that "if the only alternative is really hell or a political process, then we have got all of us to work ceaselessly for a political process."

Russia has been the main supporter of Assad's regime since the uprising began in March 2011, using its veto at the U.N. Security Council along with China to shield its last Mideast ally from international sanctions.

Lavrov said Russia would continue to oppose any U.N. resolution that would call for international sanctions against Assad and open the way for a foreign intervention in Syria. And while he again emphasized that Russia "isn't holding onto Bashar Assad," he added that Moscow continues to believe the opposition demand for his resignation as a precondition for peace talks is "counterproductive."

"The price for that precondition will be the loss of more Syrian lives," Lavrov said.

He said Assad is refusing to step down, adding that "there is no possibility to change that stance."

Both Brahimi and Lavrov insisted that efforts to end the civil war must be based on a peace plan that was approved at an international conference in Geneva in June.

The Geneva plan calls for an open-ended cease-fire, a transitional government to run the country until elections, and the drafting of a new constitution. But it was a non-starter with the opposition because of Russia's insistence that the plan leave the door open for Assad being part of the transition process and the fact that it didn't mention possible U.N. sanctions.

Brahimi said that while some "little adjustments" could be made to the original plan, "it's a valued basis for reasonable political process."

With the opposition offensive gaining momentum in Syria, there is little hope that the initiative would have any more chance of success than it had when it was approved.

Lavrov has said that Moscow is ready to talk to the main Syrian opposition group, even though it had earlier criticized the United States and other Western nations for recognizing the Syrian National Coalition for Opposition and Revolutionary Forces as the legitimate representative of the Syrian people.

On Friday, coalition leader Mouaz al-Khatib rejected the Russian invitation for talks and urged Moscow to support the opposition's call for Assad's ouster. Lavrov said Saturday that al-Khatib's statement was surprising after his earlier contacts with Russian diplomats in Egypt during which the opposition tentatively agreed on a meeting in a third country.

Lavrov said the coalition leader should "realize it would be in his own interests to hear our analysis directly from us."

Lavrov rejected the opposition claim that Russia's continuing weapons supplies to Assad's regime make it responsible for mass killings in Syria, saying that Moscow bears no responsibility for the Soviet-era weapons in Syrian arsenals. He said that defensive weapons such as anti-aircraft missiles that Russia has continued to supply to Damascus couldn't be used in the civil war.

"We aren't providing the Syrian regime with any offensive weapons or weapons that could be used in a civil war," Lavrov said. "And we have no leverage over what the regime has got since the Soviet times."

Georgy Mirsky, a leading Mideast expert with the Institute for World Economy and International Relations, a top foreign policy think-tank , said President Vladimir Putin's stand on Syria is rooted in fear that joining international calls for Assad's resignation would make him look weak at home. "It would look like an inadmissible concession to America, a virtual surrender. The Kremlin would lose its face, look like a loser," said Mirsky.

He wrote in his blog that Putin is resigned to Assad's eventual collapse and the loss of any Russian influence in a future Syria, but firmly opposes international sanctions. That stand allows Putin to tell his domestic audience that Russia has defended its ally until the end against overwhelming odds, said Mirsky.