The United States and Russia failed in talks to reestablish a cease-fire in Syria as warplanes bombarded rebel-held areas of Aleppo, killing dozens of people.
U.S. Secretary of State John Kerry reported "little progress" in getting a truce after talks in New York on September 23 with Russian counterpart Sergei Lavrov, who said no agreements were found and accused Washington of failing to honor the previous cease-fire deal.
In the western Syrian city of Aleppo, government warplanes unleashed a massive air attack on Aleppo that left dozens dead and wounded.
The Britain-based Syrian Observatory for Human Rights (SOHR) reported at least 30 air strikes had targeted different areas of Aleppo during the early morning of September 23 and said at least 27 civilians had been killed with dozens of other wounded and others still lying under rubble.
A member of the city's forensic team, Muhammad Abu Jaafar, said he had documented 54 deaths since late on September 22, including many women and children.
Hamza al-Khatib, head of a hospital in rebel-held eastern Aleppo, said that 91 people had been killed.
There were reports of as many as 40 buildings being destroyed in the attacks and a main water station damaged.
Ibrahim Alhaj, a rescue worker with the Syrian Civil Defense, also known as the White Helmets, said "I have not seen in my life such bombardment. It is very, very intense."
Dozens of other civilians were killed in air strikes on other parts of Aleppo Province, including at least 15 in the village of Bushqatin, three in Kfar Hamra, and 11 in Al-Bab, a stronghold of the Islamic State group, Abu Jafaar and SOHR reported.
The Syrian military, which is backed by the Russian air force, said late September 22 it was starting a new operation against the rebel-held eastern part of the city, which is home to at least 250,000 people.
An army source told Reuters on September 23 that the offensive would be "comprehensive," with a ground assault following air and artillery bombardment.
Rebels vowed to fight to keep President Bashar Assad's forces out of their districts and shelled government neighborhoods, wounding several people, according to state media.
Russia and the United States also failed to reach an agreement on the Syria crisis at a high-level meeting in New York on September 22.
Kerry pledged following the meeting of the International Syria Support Group on the sidelines of the UN General Assembly that Washington will continue to push for a truce to end the five-year-old war in Syria.
But he said the United States needs Syrian President Bashar al-Assad's government and his chief ally, Russia, to "do their part."
"If the Russians come back to us with constructive proposals we will listen," Kerry said following the high-level meeting, which included Lavrov and top diplomats from European and Arab nations.
He said that the Syrian support group members had "near unanimity" in their support of the peace process proposed by Washington as the only realistic path to find a resolution to the crisis.
Staffan de Mistura, the UN Syria envoy, called the meeting "long, painful, difficult, and disappointing."
With reporting by Reuters, AP, AFP, dpa, and TASS