This brief respite follows a weeks-long bombardment on parts of the city by Syria's military, backed by Russia, which has been fiercely criticized by Western powers for its deadly toll on the civilians trapped there.
It's not yet clear that any corridors have been set up, nor how many of the roughly 250,000 civilians trapped in eastern Aleppo would be able to use the brief eight-hour "humanitarian pause" promised for Thursday.
Nor does it seem likely that rebel fighters in eastern Aleppo, whether moderate or extremist, will seek to leave the city then.
"Even though that we support a truce and also humanitarian aid entering Aleppo, we are totally against leaving the city," Zakaria Malahifji, from the Fastaqim Union rebel group, told CNN. Fastaqim is one of the largest rebel factions in Aleppo and is part of the Free Syrian Army.
"We won't withdraw and there is no reason for that. Jabhat Fateh al-Sham doesn't exist in Aleppo and we will not agree on leaving the city," Malahifji added, referring to one-time al Qaeda affiliate Jabhat Fateh al-Sham, previously known as al Nusra Front.
After a short-lived ceasefire for the city collapsed last month, Russia accused the United States and its allies of failing to separate moderate rebels from extremists like the Nusra Front, as was supposed to happen under the deal.
Malahifji said the Syrian regime's objective in this latest move was to get people out of the city, and that it had used the same approach in the Damascus countryside.
"It has been done by committing a genocide and with very intensive bombardment, so they can have demographic change that the Russians are helping with. This is a very cheap method and it comes with the international community's silence," he said.
Abdulraham Almawwas, vice-president of the Syria Civil Defense volunteer group, also known as the White Helmets, told CNN Wednesday that, as of now, there are "no ways to go out of the city, it's completely under siege."
He said the people of Aleppo were also aware that after three previous ceasefires, there had been "a lot of attacks on the civilians and on hospitals," so they were waiting to see what might come next.
Almawwas, who's in charge of operational coordination for the group, spoke to CNN from Paris, where he is part of a Syrian delegation that has traveled from Aleppo to meet French leaders.
Assad: 'We need to attack the terrorists'
Meanwhile, Syrian President Bashar al-Assad said in an interview released Wednesday that the way to protect the civilians of Aleppo is to "get rid of those terrorists."
"That's our mission according to the constitution and the law. We have to protect the people, and we have to get rid of those terrorists from Aleppo. That's how we can protect civilians," Assad told Swiss channel SRF1.
"How can you protect them [the people] while they are under the control of the terrorists? They've been killed by them and they've been controlled fully by the terrorists. Is it our role to sit aside and watch? Is that how we can protect the Syrian people? We need to attack the terrorists. That's self evident."
In an interview last week with a Russian newspaper, Assad also said that his forces must continue to "clean" Aleppo
'Eight hours is not enough'
The United Nations has said that Thursday's planned eight-hour pause is not long enough to carry out any aid operations.
German Foreign Minister Frank-Walter Steinmeier also voiced his concern Tuesday.
"The cessation of hostilities in and on Aleppo for a few hours on Thursday, as announced by Moscow, can only be the starting point," he said in a statement.
"Although a suspension of the airstrikes is very welcome, eight hours are by no means enough time to provide the urgently needed humanitarian access to the people under siege in eastern Aleppo. More can be done -- and it is a humanitarian imperative to do more."
UN Special Envoy for Syria Staffan de Mistura warned Monday that "between now and December, if we cannot find a solution, Aleppo will not be there any more
," according to a transcript released by the UN.
He also urged the world not to overlook the plight of Aleppo while eyes are focused on the operation to wrest Mosul from ISIS control
in neighboring Iraq.
The self-declared water directorate in eastern Aleppo said Tuesday that 80% of the public water supply network was out of service following weeks of bombardment, with damage to 18 pipelines preventing the provision of safe drinking water to 45 neighborhoods, or 200,000 people, in besieged areas of the city.
"In the light of what Aleppo city witnessed in the past 27 days, we estimate that the whole water system will become out of service by the end of the current month," it said.
War crimes accusations
As the strikes in Aleppo have continued, killing hundreds of civilians, Western powers have accused Assad and his supporters of war crimes.
Both the United States and United Kingdom have mulled
potential economic sanctions against Syria and Russia due to the Aleppo crisis.
Kremlin spokesman Dmitry Peskov told reporters that the planned truce is a "manifestation" of the Russian military's "goodwill."
"This is an obvious continuation of Russian efforts, on the one hand, to fight terrorists in Syria, and on the other, to unblock the situation in Aleppo," he said Tuesday. "It is exclusively a manifestation of goodwill by the Russian military."