"We stressed again that in our view there was no military solution to this conflict," Brahimi said in a joint statement read out after his closed-door talks with US Deputy Secretary of State William Burns and Russian Deputy Foreign Minister Mikhail Bogdanov.
They agreed on the need to reach a political solution based on an agreement reached by foreign powers in Geneva last June, which called for a transitional period in Syria. That left open the question of what role, if any, Syrian President Bashar al-Assad would have.
That appeared to be sticking on point at Friday's meeting.
"The devil is in the details," Brahimi told reporters.
"We said that this transitional government that will be in charge during the transitional period only, it is not a government that will stay for a long time, it will direct the transitional period that will end with the holding of the elections that will be agreed upon," he said in Arabic, adding that it would have "all powers of the state".
But asked by a reporter if there are had been any concrete progress, he said: "If you are asking whether there is a solution around the corner, I'm not sure that is the case."
The United States, European powers and Gulf-led Arab states insist Assad must step down to end a war that has killed 60,000 people in nearly two years. Russia says this must not be a precondition to a settlement.
Syria denounced Brahimi as "flagrantly biased" on Thursday, casting doubt on how long the UN-Arab League mediator can pursue his peace mission.
Brahimi, speaking to Reuters in Cairo a day earlier, said Assad could have no place in a transitional government to end the civil war, the closest he has come to calling directly for the embattled president to quit.
Asked on Friday whether the Russians shared his views, he replied: "I am absolutely certain that the Russians are as preoccupied as I am, as preoccupied as the Americans are, by the bad situation that exists in Syria and its continuing deterioration.
"I am absolutely certain they would like to contribute to its solution," he added.
But pressed on whether Bogdanov had come with new proposals to pave the way for a political transition, he said: "We discussed a lot of things. They had ideas, others also had ideas."
Earlier, a US official said the talks would focus on creating the conditions for a political solution, specifically the transitional body agreed on in June.
"The US position is clear: Assad has lost all legitimacy and must step aside to enable a political solution and a democratic transition that meets the aspirations of the Syrian people," the US official said, asking not to be named.
Before the meeting, Bogdanov gave no indication Russia would abandon its insistence that Assad must not be forced out by external powers.
Russia is "eagerly awaiting bringing the agreements reached in Geneva to life without damaging the sovereignty and territorial integrity of Syria and without violating the right of the Syrian people to choose their own leaders," Bogdanov was quoted as telling Russia Today television.
