A spokeswoman for the Syrian opposition's High Negotiations Committee (HNC) told The Associated Press that the United Nations must be involved in peace talks. The statement came after a call by Russian President Vladimir Putin for a new round of negotiations between the Syrian government and opposition representatives.

Bassma Kodmani said the HNC - which represents several Syrian opposition groups - was "completely in favor of those talks, but we want them under UN auspices."

She called on Russia to seek a process "acceptable to credible opposition and regional players," adding that the HNC didn't believe that Astana, the Kazakh capital which was cited by Putin as a venue for the talks, was "the appropriate place."

'UN role critical'

The HNC walked out of several rounds of UN-mediated peace talks earlier this year in Geneva, lambasting the refusal of the Syrian regime to lay down its arms.

Putin has called for a nationwide ceasefire and a new round of peace talks brokered by Moscow and Ankara.

His call followed a peace agreement that allowed the start of an evacuation of civilians and rebel fighters from war-ravaged eastern Aleppo, which the Syrian regime is on the verge of recapturing.

Although several thousand residents - including many women, children and the wounded - were removed by buses to safer areas, the evacuation was suspended on Friday after fighting resumed in the northern Syrian city.

Journalists and aid agency workers continued to post social media updates from eastern Aleppo, including Robert Mardini, regional director for the International Red Cross. Mardini quoted one of his colleagues on the ground, who said she had "never seen such levels of human suffering before."

The Syrian regime and the opposition traded blame for halting the evacuations, with Syria's state news agency SANA saying buses had come under sniper fire from rebels.

UN High Commissioner for Refugees Filippo Grandi warned that if all civilians were not allowed out of Aleppo quickly, the suffering in the city was doomed to be repeated.

"There is grave risk now that such displacement and suffering will not stop, but will be repeated elsewhere, in other wars. For the sake of civilian protection everywhere, Syria's conflict must be ended, now, and without delay," Grandi said in a statement on Saturday, adding: "Civilians should not be hostage to negotiations."

Security Council to vote

The UN Security Council held a closed emergency meeting on Friday to discuss a French-German proposal for independent teams to monitor the evacuation of civilians and fighters. Diplomats agreed to convene again over the weekend for further talks.

Washington said it supports the plan, but Vitaly Churkin , Russia's ambassador to the UN, called it "questionable."

Reports differ on how many people remain in the Aleppo enclave, ranging from 15,000 to 40,000 civilians, along with an estimated 6,000 fighters.

In his end-of-year press conference, US President Barack Obama accused Syrian President Bashar al-Assad's regime, Iran and Russia of having blood on their hands over the carnage in the devastated city.

He warned Assad that he would not be able to "slaughter his way to legitimacy."

Obama said Washington could have done little to stop the war, short of a full military takeover of Syria.

He joined the call for international observers to monitor the evacuation of civilians from eastern Aleppo.

mm/ls (AFP, AP, dpa, Reuters)