Aid workers in the devastated Syrian city of Aleppo say Syria and its Russian allies stepped up their bombing campaign on rebel-held eastern parts of the city Monday, killing nearly 100 people on the fourth consecutive day of mayhem and death.
Relief workers from the Society of Anglican Missionaries, writing on Twitter, said the dead included children. They also said medical personnel and hospitals are "overwhelmed," with no additional supplies arriving.
U.S. Secretary of State John Kerry, responding to those reports, said the Syrian government of President Bashar al-Assad and its Russian allies "seem intent on taking Aleppo and destroying it in the process."
Kerry also discounted a televised report from Damascus quoting a top Syrian diplomat as saying the Assad government is prepared to take part in a unity coalition.
"While they're pounding Aleppo, dropping indiscriminate bombs, killing women and children, talk of a unity government is pretty complicated," Kerry said from the Colombian city of Cartagena.
Monitors from the Syrian Observatory for Human Rights say nearly 250 people have been killed in Aleppo and outlying areas since a shaky cease-fire disintegrated earlier this month. That truce, negotiated by Russian and U.S. diplomats, was called to allow aid workers to distribute critically needed food and medicine to hundreds of thousands of civilians cut off from supplies.
However, observers, pointing to the deadly bombing of a relief convoy last week near Aleppo, say the cease-fire failed almost from the beginning.
The onslaught at Aleppo triggered a flurry of accusations Sunday at an emergency session of the U.N. Security Council.
U.S. Ambassador Samantha Power accused Russia and Syria of conducting an "all-out offensive" to retake the divided city.
"Instead of pursuing peace, Russia and Assad make war. Instead of helping get lifesaving aid to civilians, Russia and Assad are bombing the humanitarian convoys, hospitals and first responders who are trying desperately to keep people alive," she said.
Power has repeatedly lambasted the Assad government and its Russian allies for their ongoing assault on the city, and Sunday she described Russia's role in the conflict as "barbarism."
She was joined by British diplomats and French Ambassador Francois Delattre, who said "war crimes are being committed here in Aleppo." He then described Aleppo as a "martyred city."
Kremlin spokesman Dmitri Peskov, speaking Monday, denounced the latest Western accusations of complicity in the destruction of Aleppo, pointing to what he called "the overall unacceptable tone and rhetoric of the representatives of the United Kingdom and the United States."
Peskov also told reporters that Moscow remains "gravely concerned" by what it sees as "terrorists" in and near Aleppo using the tattered cease-fire to rearm and attack Syrian government forces.
Referring to evidence of al-Qaida-linked extremists fighting alongside rebels in Aleppo, Peskov said, "There has been no separation of moderates from terrorists.
Naturally," he said, "the fight against terrorists is ongoing, and it must not be stopped."
Aleppo, the country's largest city, has been divided among government troops, rebel militias, Islamic extremists and Kurdish fighters since 2012 -- a year after the country erupted into civil war.
U.N. officials estimate that 400,000 people - most of them civilians - have been killed since then.