Residents flee as air strikes shake Syria's Aleppo

A front loader operates at a site hit by airstrikes in the rebel held area of Aleppo, Syria on April 28, 2016.

Terrified residents fled a new wave of air strikes on rebel-held areas of Syria's second city Aleppo on Saturday, as a "freeze" in fighting held on two other fronts.

Aleppo was left out of the temporary US-Russian brokered truce, which appeared intact in the regime stronghold of Latakia as well as Damascus and the nearby rebel bastion of Eastern Ghouta.

In Aleppo's rebel-held east, dozens of civilians left the battered district of Bustan al-Qasr early on Saturday morning, an AFP correspondent said.

"The situation has become unbearable," Abu Mohammed said as he prepared to flee with his wife and five children.

"One of my kids is terrified by the bombing and no one has been buying anything from my shop for a week," said the household appliance salesman. "Everything is paralysed."

Once Syria's economic hub, Aleppo and its surrounding countryside have suffered some of the worst fighting in a conflict that has killed more than 270,000 people and displaced millions.

The city has been divided between regime control in the west and rebel control in the east since 2012.

More than 246 civilians have died in shelling, rocket fire and air strikes in both sides of the city since April 22, the Syrian Observatory for Human Rights monitor said.

At least six civilians died in rebel-controlled areas on Saturday, including Bab al-Nairab and Bustan al-Qasr districts, the civil defence said.

The few people out on the streets in the city's east watched the sky anxiously for regime aircraft, running for shelter when one launched a new raid.

The Britain-based Observatory, which relies of a wide network of sources on the ground, reported 28 air strikes on the area.

Some families have fled to safer districts nearby. Others left by the dangerous Castello road, the only route out of near-besieged east Aleppo that has been targeted by air strikes and shelling.

Hospitals have also been bombed in nine days of escalating violence in Aleppo.

A total of four medical facilities were hit in Aleppo Friday on both sides of the front line, according to the International Committee of the Red Cross.

A raid on Wednesday hit a hospital supported by Doctors Without Borders and the Red Cross as well as nearby housing, killing 30 people in an attack UN chief Ban Ki-moon condemned as "inexcusable".

That strike also killed Mohammad Wassim Maaz, one of the last paediatricians in the rebel-held side of the city.

Samar Hijazi, head of the archives at the hospital, said the doctor was "totally devoted" to his patients.

"He examined about a hundred children a day," she said. "The hospital was almost his home. He stayed until late at night."

"I once saw him crying because he hadn't managed to save a child with internal bleeding after being shot by a sniper," she said.

Hospitals still operating in rebel areas are very few and "medical staff is exhausted," she said.

On other fronts, fighting halted at 1:00 am Saturday (2200 GMT Friday) in a "freeze" set to last for 24 hours in Damascus and Eastern Ghouta, and 72 hours Latakia.

In northeastern Syria, a suicide bomber killed five Kurdish policemen at a checkpoint in the city of Qamishli, police said.

It was not immediately clear who carried out the attack, but the Islamic State (IS) group has claimed previous bombings in the mainly Kurdish city.

The violence in Aleppo has severely tested a February 27 truce between the regime and non-jihadist rebels intended to pave the way to an end to the five-year conflict.

A new round of UN-backed peace talks is set to start on May 10 in Geneva.