The evacuation of Aleppo should take no more than two days, Russian and Turkish foreign ministers say, following a rare breakthrough and show of unity by world powers over Syria that allows UN monitors to observe the operation.
A total 37,500 evacuees have so far left the war-torn Syrian city and the goal is to complete all evacuations by Wednesday, Mevlut Cavusoglu, Turkish foreign minister, wrote on Twitter on Tuesday.
The evacuation of of Aleppo would be complete in a maximum of two days, Sergey Lavrov, Russia's foreign minister, said.
Lavrov said that Russia, Iran and Turkey had used their influence to make the evacuation happen and that the 19-member International Syria Support Group including Saudi Arabia, Egypt and the US had not been able to enforce its decisions.
Cavusoglu travelled to Moscow after holding talks with his Russian and Iranian counterparts to discuss the future of Syria.
At a meeting on Tuesday in the Russian capital, Turkey, Iran and Russia agreed to guarantee the Syria peace talks and backed expanding a ceasefire in the country, laying down their claim as the main power brokers in the conflict.
"Iran, Russia and Turkey are ready to assist in preparing the agreement in the making between the Syrian government and the opposition and to become its guarantor," Lavrov said, citing a joint statement.
"The ministers agree with the importance of widening the ceasefire, of free access for humanitarian aid and movement of civilians on Syrian territory."
Cavusoglu said in comments translated into Russian that the ceasefire should cover the entire Syrian territory but exclude the Islamic State of Iraq and the Levant (ISIL) group and the Jabhat Fateh al-Sham (formerly known as al-Nusra Front, which was linked to al-Qaeda).
For its part, the Syrian government has authorised the UN to send an additional 20 expatriate staff to east Aleppo, where they will monitor the ongoing evacuation of thousands of people, according to a UN spokesperson.
Jens Laerke, speaking in Geneva, said: "This will almost triple the number of international staff currently deployed to Aleppod.
"The task is to monitor and observe the evacuations."
The UN Security Council on Monday unanimously called for UN officials and others to observe the evacuation and monitor the safety of civilians.
The UN staff, already in its Damascus office, will travel to Aleppo "as soon as possible", Laerke said.
Aleppo, Syria's second city, was once a cultural and economic hub before being split between government and rebel control in late 2012.
Al Jazeera's Charles Stratford, reporting from Reyhanli in neighbouring Turkey, said there were concerns about "the kind of access" UN monitors would be granted once they are in Syria.
"There are reports of harassment by some of the Iranian-backed militias in that area," he said.
"And of course ... there are concerns about how rebel forces may cooperate."
Arrivals in Idlib
According to UN aid partners, the number of people who had arrived in Idlib - where Aleppo evacuees are being taken - was around 19,000, the UN's Laerke said.
"We do not have independent UN access to the buses, so we are not able to enter and access people; that does not take away from the protection concerns that we do have and continue to have," he said.
About 43 unwell people were medically evacuated from east Aleppo on Monday, bringing the total to 301 since last Thursday, according to Tarik Jasarevic, World Health Organization's spokesman.
"Out of those 301, 93 patients were referred to hospitals in Turkey, others are in hospitals in [opposition-held] Idlib and western rural Aleppo."
The vast majority have trauma injuries. The sick and wounded include 67 children, Jasarevic said.
|Syria's conflict started as a largely unarmed uprising against President Bashar al-Assad's rule in March 2011 [Emrah Gurel/AP]
The UN refugee agency UNHCR said there was no sign of a heavy influx of people fleeing Aleppo into neighbouring Turkey.
"All the borders of Syria are very tightly managed at present. People, we understand, are being allowed to cross into Turkey when they come. But I think this is speculative as we are not yet seeing people move across in relation to Aleppo," Adrian Edwards, UNHCR spokesperson, said.
Laerke said some 750 people have been evacuated from Foua and Kefraya, two Shia-majority villages besieged for months by rebel groups.
Syria's conflict started as a largely unarmed uprising against President Bashar al-Assad's rule in March 2011, but it quickly turned into a full-scale civil war that has killed hundreds of thousands.
Attempts to negotiate a lasting ceasefire have failed time and again.
Source: Al Jazeera and news agencies