Syrian Government says the operation to move people away from four besieged towns in the north western region has begun.
According to AFP reports, the people evacuated from Foah and Kefraya, two government-held towns, have arrived in Rashideen, west of Aleppo.
Similar operations have also begun in rebel-held Madaya, near Damascus.
In March, the United Nations described the situation in the towns as catastrophic, with more than 64,000 civilians trapped in a cycle of daily violence and deprivation.
Many people are reported to have died as a result of shortages of food or medicine.
Officials said more than 30,000 people would be moved.
The US Secretary Of State, John Kerry, has vowed to investigate all alleged violations of the partial truce in Syria.
“We are digging in through the process we set up to find out if in fact a violation did take place or was it in fact a legitimate engagement against Nusra only or Daesh only,” Kerry said in a news conference with German Foreign Minister Frank-Walter Steinmeier.
Kerry said that while there were reports of violations, the vast majority in Syria had seen a decrease in violence.
“So we call on all the parties not to be looking for a way to get out from under the responsibility of the cessation of hostilities, but rather to help the process to hold itself accountable,” Kerry added.
He says the US and Russia are working on a mechanism to ensure any airstrike solely targets so-called Islamic State (IS) or al-Qaeda-linked Nusra front.
Mr Kerry however says they have agreed not to debate alleged violations in public.
He added that he was concerned by reports that the Syrian government was creating obstacles for the delivery of humanitarian aid and hoped it would stop its officials and troops from taking medicines or other supplies from the shipments.
In the meantime, aid convoys have begun reaching besieged areas of Syria as the cessation of violence that began on Saturday appears to be holding.
But France expressed concern about reports of strikes by Syrian government and Russian aircraft on areas controlled by mainstream rebels.
Amid a partial truce in the Syrian war, the United Nations says it plans to deliver aid to about 150,000 Syrians in besieged areas over the next five days.
The UN said that it is ready to help an estimated 1.7 million people in hard-to-reach areas by the end of March.
A cessation of hostilities began on Saturday and there have been complaints of breaches from both sides.
But it otherwise appeared to be intact with a key Syrian opposition group saying the situation was much better.
The UN’s humanitarian Coordinator in Syria, Yacoub el-Hillo, called the truce “the best opportunity that the Syrian people have had over the last five years for lasting peace and stability”.
The organisation plans to use the lull to deliver food, water and medicine to towns like Madaya, where residents have reportedly been starving to death.
The UN estimated that almost 500,000 people are living under siege in Syria.
The cessation of hostilities was agreed as part of a plan by the US and Russia, who have backed opposing sides in Syria’s civil war.
It does not apply to the fight against the so-called Islamic State (ISIS) or the Nusra Front, which is linked to al-Qaeda.
Another 16 people have been starved to death in the besieged Syrian town of Madaya.
This was revealed by the Medical Charity, Medecins Sans Frontieres (MSF) as the Syrian peace talks get underway in Geneva.
The Medical Charity said that there were also 33 people in danger of dying.
According to BBC, the MSF Operations Director, Brice de la Vigne, disclosed that the situation was ‘totally unacceptable’ when people ‘should have been evacuated weeks ago’.
The MSF had previously said that 30 people died of starvation in the town late last year.
Earlier in January, two emergency convoys of food and aid supplies were delivered to Madaya, up to 40,000 people were believed to be trapped in appalling conditions.
United Nations Humanitarian Chief has called for the evacuation of some 400 people in the besieged town of Madaya for medical treatment.
Stephen O’Brien said this after the UN Security Council discussed the crisis in the town near Damascus.
“We found some 400 people who must be evacuated Immediately for medical treatment or face dying,” he said.
An aid convoy had earlier brought food to 40,000 residents of Madaya town in Syria, who have been under government siege for six months.
The UN said it had received credible reports of people dying of starvation in Madaya.
According to reports, people were believed to be eating pets and grass to survive in Madaya, near Lebanon’s border.
Simultaneously, aid lorries also entered two towns besieged by rebel forces in the northern province of Idlib under a deal between the warring parties.
The situation in Foah and Kefraya was also said to be extremely dire with an estimated number of 20,000 people trapped there since March.
According to SANA, Syria’s state news agency, 65 trucks loaded with aid supplies entered Madaya and the other besieged towns, Foua and Kefraya.
It was reported that the sight of food trucks brought starving residents to tears.
Reports from the UN refugee agency says about 40,000 people are believed to be eating pets and grass to survive in Madaya, near Lebanon’s border.
In this vein, the United Nations (UN) has directed an aid convoy to leave for Madaya, which was said to be under government siege and its residents, reported to be starving to death.
The plight of Madaya in Syria has drawn international attention, partly due to images emerging of severely malnourished residents.
The town had been besieged since early July by the government forces and their allies.
About 4.5 million people in Syria live in hard-to-reach areas, including nearly 400,000 people in 15 besieged locations who do not have access to life-saving aid.