As Russian, Syrian forces attack Aleppo, the linchpin in civil war, the intent behind Russian's humanitarian corridors is being questioned by the US, France and aid organisations.
Central Intelligence Agency Director John Brennan said on Friday he was not optimistic about the future of Syria.
"I don't know whether or not Syria can be put back together again," Brennan told the annual Aspen Security Forum. His comments were a rare public acknowledgement by a top US official that Syria may not survive a five-year civil war in its current state.
"We need to be able to have some sense that Assad is on the way out […] it needs to be clear that he is not part of Syria's future. Until that happens until there is at least the beginning or the acknowledgement of that transition."
The CIA director added, "…I don't know whether or not Syria can be put back together again whether it's going to be some type of confederal structure where the various confessional groups are going to have the lead in governing their portions of the country."
Brennan also expressed caution, saying Iraq issue needed to be addressed for "some semblance of tranquillity in Syria".
Similar fears about Syria's future were made by US Secretary of State John Kerry in February 2016 when President Bashar al Assad and rebel groups were to accept a cease fire plan.
Kerry had warned "real decisions" about a political transition were essential over the next few months or else things could get uglier.
"It may be too late to keep it as a whole, Syria, if we wait much longer," he said.
On July 28, 2016, Assad offered an amnesty deal to rebel fighters and Russia insisted those who surrender would be allowed passage from Aleppo through three humanitarian corridors.
As Russian and Syrian forces escalate their assault on Aleppo, the corridors come as a sign of a changing tide. When the city was taken over in large parts by rebel forces, it was seen as a sign of Assad's imminent downfall. The last two months have seen regime forces push back – successfully, leading other stakeholders to wonder what the offer of a humanitarian corridor actually means.
According to Kerry, the US was trying to determine whether a Russian plan for a humanitarian operation in Syria is sincere.
He said on Friday that if it proves a "ruse" it could ruin cooperation between Moscow and Washington.
Examining the corridor offer
Previous amnesty offers have resulted in the separation of men from their families, with no indication of if and when they would be returned.
According to news agency Reuters, many of the 250,000 civilians trapped for weeks inside the besieged rebel-held sector of Aleppo have so far stayed away from "safe corridors" that Moscow and Damascus promised for those trying to escape the most important opposition stronghold in the country. However, RT.com suggests civilians were being prevented from leaving by rebel forces.
US officials have suggested the plan may be an attempt to depopulate the city so the Syrian army can seize it. The Syrian opposition called it a euphemism for forced displacement of the inhabitants, which it said would be a war crime.
Aleppo, Syria's biggest city before the war, has been divided since 2012 into government and rebel sectors. Retaking it would be the biggest victory for Assad in five years of fighting, and demonstrate the dramatic shift of fortunes in his favour since Moscow joined the war on his side last year.
This would also be an embarrassment for Kerry, who has led a diplomatic initiative with Moscow aiming to let the Cold War superpower foes cooperate against terrorist groups such as DAESH and restore a ceasefire for the wider civil war which collapsed in May.
Asked about the Russian operation, Kerry said Washington was still unsure of Moscow's intent: "It has the risk, if it is a ruse, of completely breaking apart the level of cooperation."
He said, "On the other hand, if we're able to work it out today and have a complete understanding of what is happening and then agreement on the way forward, it could actually open up some possibilities." He said he had spoken with Moscow twice in the past 24 hours to try to clarify Russian intentions.
The White House also voiced its doubts. "Given their record on this, we're sceptical, to say the least," White House spokesman Eric Schultz said at a news briefing.
France also said the Russian plan for humanitarian corridors to allow residents of Aleppo to flee the besieged Syrian city were not a "credible response".
France's Foreign Ministry said the city's residents should have access to aid under international humanitarian rules and remain safely at home.
"In this context, the idea of 'humanitarian corridors' consisting of asking Aleppo's residents to leave the city does not offer a credible response to the situation," the ministry said in a statement.
However, Interfax news agency quoted Russian Deputy Defence Minister Anatoly Antonov as saying on Friday that Russia's operation in the Syrian city of Aleppo is exclusively humanitarian.
"We are ready to do everything we can to deliver aid to peaceful citizens who are hostages of the terrorists, and even to those militants who wish to lay down arms," Antonov was quoted as saying.
Does Aleppo need evacuation?
The fate of Aleppo in the coming weeks has the potential to be a turning point in a seemingly endless, multi-sided civil war that has killed hundreds of thousands of people, driven millions from their homes and drawn in most world and regional powers.
Pro-government forces with Russian backing have advanced in the three months since the ceasefire collapsed, and imposed a siege on the rebel-held sector of Aleppo since early July when they closed the main road out of the city.
The United Nations says food will run out within weeks for the people trapped inside, and has been trying to negotiate regular pauses in the fighting to allow humanitarian access.
"The ICRC is not a big fan of humanitarian corridors, because it always runs the risk that there is the concept of safe areas, and everything outside those safe areas becomes an area of non-respect for international humanitarian law," International Committee of the Red Cross Middle East regional head Robert Mardini told reporters in Geneva.
Save the Children quoted a doctor describing dire conditions of constant bombardment and mass casualties inside the city.
At one bombing site, "a child less than 10 years old ran to me shouting 'sir, please put my arm back'. His left arm was amputated and he held it with his right hand. He was begging me to put it back, and this is only one of so many tragedies that we see," a doctor said in a statement released by the aid group.
So far, the safe zones have not been used. Syrian state television has also accused rebels of preventing civilians from leaving, which rebels deny. A state TV reporter in Aleppo said reception centres with health and food supplies had been set up around Aleppo to receive civilians, but so far few had come through because rebel fighters were threatening them.
The main opposition High Negotiations Committee (HNC) says it believes the aim is to cleanse the area so government forces can capture it.
"The world must not allow Russia to get away with disguising its assault on Aleppo with deceitful talk about humanitarian 'corridors.' Be clear - these 'corridors' are not for getting aid in, but driving people out. The brutal message to our people is - 'leave or starve'," HNC member Bassma Kodmani said.
Privately, US officials fear the Russian proposal masks the real intent of its Syrian ally, to separate boys and men from the rest of the population, claim they are terrorists and either imprison or execute them, "as Assad and his father have done repeatedly at least since 1982," said one official, discussing Washington's analysis on condition of anonymity.
"Why would you evacuate a city that you wanted to send humanitarian aid to?" asked a second official.
Ghaith Yaqout al-Murjan, an activist in Aleppo, told Reuters civilians were avoiding the corridors as they were still unsafe.
"There are people who want to leave because they can no longer bear the shelling by helicopters, jets, barrel bombs. ... The rebels are not holding anyone if they want to leave."
Al Murjan added, "You are talking about the need to walk a kilometre in a battle where you are at risk of being hit from two sides."
UN intervention in humanitarian corridor plan
The United Nations, which hopes to resume peace talks in August, said safe corridors out could only be helpful if combined with humanitarian access for those who do not want to leave.
UN mediator Staffan de Mistura said there was "urgent need for improvement".
Regular pauses for humanitarian access were necessary, he added.
"The second suggestion is to actually leave the corridors, which are being established at their initiative, to us," he added.
In response, Russian UN ambassador, Alexei Borodavkin, said Moscow would "carefully study" Mistura's comments and take them into account, RIA news agency reported. However, Borodavkin stopped short of promising to comply with them.
Early in his tenure as Syrian peacebroker, Mistura tried and failed to foster a local ceasefire in Aleppo in hope of turning it into a nationwide truce.
The UN mediator suggested on Friday that if done right, a humanitarian plan for Aleppo could still help restore confidence in the wider peace process.
"Aleppo is becoming, as it always was, an iconic place which can make the world believe there is a human political solution in Syria," he said.