Lakhdar Brahimi, the joint United Nations-Arab League envoy to Syria, has met opposition figures tolerated by the government for talks on resolving the crisis engulfing the country.
Brahimi held talks on Tuesday at his Damascus hotel with a delegation of six people led by Hassan Abdel Azim, head of the National Coordination Committee for Democratic Change (NCCDC), an opposition group permitted to exist by the regime.
Abdel Azim said after the meeting that Brahimi would stay in Syria until Sunday "to try to implement an international consensus to end the crisis".
His deputy Raja Nasser said: "The only solution is a transitional government that holds all powers".
"A political solution is the only solution, and this means the establishment of a new democratic regime instead of the current regime," Nasser said.
The comments came in the wake of a report in a French daily newspaper that spoke of a US-Russian initiative for a transition in Syria, which has caused rage among opponents who reject any compromise with the government.
The Le Figaro newspaper said a solution in the offing would involve keeping President Bashar al-Assad in power until 2014 while preventing him from further renewing his mandate.
The Local Co-ordination Committees (LCC), a grassroots network of anti-regime activists, blasted Brahimi and the international community for failing to stop the bloodshed.
"Brahimi's arrival in Damascus to discuss a new political initiative to solve the crisis caused by the regime... has not put a stop... to massacres," the LCC said in a statement.
It said the LCC rejects "any initiative that puts Syrians in a position where they are extorted and forced to choose between accepting unfair compromises, or the continuation of the regime's crimes against them".
The veteran diplomat arrived in Syria on Sunday and discussed solving the country's ongoing conflict with Assad on Monday. Diplomats said the talks with Assad produced no sign of a willingness to negotiate.
Brahimi has made little progress toward brokering an end to the conflict since starting his job in August, primarily because both sides adamantly refuse to talk to each other.
The government says the rebels who are fighting it, which it describes as foreign-backed terrorists, are set on destroying the country.
Syria's rebels say that forces under Assad's command have killed too many people for him to be part of any solution.
Activists say more than 40,000 people have been killed since the Syrian uprising began in March 2011.
Opposition fighters continue to secure military victories, the latest being the takeover of Harem town in the northern Idlib province.