Syria Army Advances in Aleppo, Calls on Rebels to Leave City

Syrian regime forces advanced Sunday in Aleppo after Russia unleashed dozens of air strikes, as the U.N.'s top aid official decried the "living hell" suffered by residents in the city's rebel-held east.

The devastating five-year war in Syria has ravaged second city Aleppo, once the country's economic hub but now torn apart by fighting between government troops and rebel forces.

The army of President Bashar Assad announced a major push on September 22 to capture Aleppo's opposition-held east and has gained ground in the city with the help of ally Moscow.

Dozens of air strikes pounded multiple battlefronts in the devastated city on Sunday, AFP's correspondent said. 

The Syrian Observatory for Human Rights said Russian raids "helped regime forces to advance in the north of the city," where they reached the outskirts of the opposition-held al-Heluk district.

If loyalist fighters seize al-Heluk, Bustan al-Basha and Sakhur -- all rebel-controlled neighborhoods in Aleppo's north -- they will confine opposition factions to a small section of the city's southeast.

Assad's Russian-backed military campaign in Aleppo has sparked international outrage after a series of air strikes on civilian infrastructure, including most recently on the largest hospital in the city's east.

Two barrel bombs hit the M10 hospital on Saturday, according to the Syrian American Medical Society (SAMS), which supports the facility.

United Nations aid chief Stephen O'Brien fiercely criticized the attack and called on Sunday for immediate action to end the "living hell" of civilians in Aleppo's east.

"The health care system in eastern Aleppo is all but obliterated. Medical facilities are being hit one by one," O'Brien wrote.

- 'Unjustifiable' attacks -

O'Brien said the latest indiscriminate bombings subjected residents to "a level of savagery that no human should have to endure.

"The clock is ticking. Stop the carnage now," he added.

At the bombed hospital Saturday, an AFP journalist saw bloodstained hospital beds and dented equipment lying in disarray beneath blown-out windows.

"The hospital is being destroyed! SOS, everyone!" said SAMS radiologist and hospital administrator Mohammad Abu Rajab in an audio message distributed to journalists.

M10 had already been hit on Wednesday along with the second-largest hospital in the area, M2.

That bombardment badly damaged the two facilities and left only six fully functional hospitals in east Aleppo, according to SAMS.

On Saturday, European Parliament president Martin Schulz called the hospital bombing a "war crime," tweeting that the international community "must unite to prevent (the) city's annihilation."

French Foreign Minister Jean-Marc Ayrault said "the systematic targeting of structures and health workers is particularly unjustifiable."

The World Health Organization has called Syria the world's most dangerous place for health workers, and Aleppo in particular has seen much of its medical infrastructure destroyed or heavily damaged.

- 'Safe passage' for rebels -

Syria's armed forces on Sunday called on rebel fighters in east Aleppo to abandon their positions "and let civilians live their normal lives."

"The Russian and Syrian armies will secure safe passage and aid" to any opposition fighters that defect, said the statement, distributed on Syrian state news agency SANA. 

Also on Sunday, Russian strikes in the central Syrian province of Hama killed six members of a rebel group that has received U.S. backing, according to the Observatory. 

Observatory head Rami Abdel Rahman said 13 Russian raids targeted a base used by Jaish al-Izzah, which was also hit by Moscow's warplanes in the early days of its military intervention in Syria last year. 

Diplomatic efforts to put an end to Syria's war -- which has killed more than 300,000 people -- have all but collapsed.

Russia and the United States brokered a ceasefire deal in early September, hoping it could open a path to peace -- but the truce fell apart a week later.

Relations between the two world powers have since been strained, but their top diplomats have continued to seek a way forward.

Russia said its Foreign Minister Sergei Lavrov spoke to his American counterpart John Kerry on Saturday and they "examined the situation in Syria, including the possibility of normalizing the situation around Aleppo."

They spoke again later that evening, the foreign ministry in Moscow said on Sunday, without providing additional details.