The Syrian city of Aleppo has mostly fallen to regime forces, leaving opponents of the brutal rule of President Bashar al-Assad feeling hopeless after enduring days of bombardment with an almost complete lack of medical care.

Aid workers described horrific conditions — a lack of medicine and medical supplies, a lack of ambulances, and bodies buried under rubble.

"Nothing could explain the medical situation," Abdusalam Daeif, a doctor from the Syria Relief and Development organization, told Business Insider via WhatsApp. "A lot of injuries on the streets. No one could help them. No ambulance cars. No medical points. It is impossible to count them."

The White Helmets, which have been praised for their work as first responders inside Syria, have described a dire situation.

Over "100,000 civilians are packed into a tiny area," the organization tweeted Monday. "Bombing + shelling relentless. Casualties unimaginable. Bodies lie where they fell."

Aid workers who regularly risk their lives to save civilians, meanwhile, say there's not much more they can do to help the situation in Aleppo.

"We hear children crying, we hear calls for help, but we just can't do anything," the White Helmets tweeted. "We're being bombed continuously."

Daeif has staff on the ground in Aleppo, where he says only one hospital is still functional. All other health facilities have reportedly been destroyed.

But even the one functioning hospital has run out of supplies, Daeif said.

"They receive more than 350 injuries per day," he said. "They used all medical supplies and drugs last month."

Abu Faisal, a Syrian aid worker who goes by a pseudonym and works with various groups inside the country, said he's not sure what has happened to people he's worked with in Aleppo.

"There are no aid operations or any type of municipal or civil services running and nor is there any type of organization on any level at all, just people running around as the bombing gets worse and the area gets smaller," he told Business Insider via email. "There is not much more room to run or hide and it's all chaos. For most of our friends and contacts we work with, we don't know if they are dead, captured or surrendered to the regime."

He described widespread destruction that surpasses what has been seen in the war to date.

"Every single project in Syria (except for a handful in Idleb) we built over the last four years has been destroyed in the last six months," Faisal said. "Clinics, bakeries, schools, factories, coffee shops, farms, distribution centers ... all of it is gone."

Faisal made a plea for help from foreign countries that have so far been reluctant to increase their involvement in the war.

"Trying to keep our aid operations alive is futile against all of the politics," he said. "I know people are sick and tired of hearing us Syrians, but I swear to God all anyone ever wanted was to be treated no better than animals — not even humans, just animals."

Rebel groups announced Tuesday that they had reached a ceasefire deal with Russia to evacuate some opposition forces and civilians from the city. About 40,000 people will be allowed to leave. There are about 70,000 civilians still trapped in rebel-held areas of Aleppo.

Rebels, including some terrorist factions, have been fighting the brutal Assad regime for more than five years. Assad has hung onto power with the help of allies like Russia and Iran.

Despite the significant terrorist presence inside Syria, many civilians say the Assad regime is their main enemy. The regime, through indiscriminate bombing and other brutal tactics, has killed more Syrian civilians than terrorist groups.

Faisal seemed resigned to the fact that Assad will likely remain in power.

"If I or anyone knew Assad would have done all of this just to sit on his throne then best we let him sit on it and live like animals, it's better than what people are going through now," he said. "What I do know is that if Assad thinks he can rebuild his regime on the graves of Syrians using his foreign armies, he won't last long, we will be back."