Violence in Syria killed nearly 90 people on Sunday, more than a third of them in random shelling of Hama city by troops retaliating for losses suffered in clashes with rebels, a watchdog said.
The Syrian Observatory for Human Rights said on Monday that 34 people were killed in Hama, where fighting between the army and rebels had broken out before the central city came under machinegun and rocket fire.
"When the army sustained losses, it started to arbitrarily shell residential areas," the Britain-based monitoring group's Rami Abdel Rahman told AFP in Beirut.
"Even if there were clashes between regime and rebel forces, the army should never arbitrarily bomb residential areas, which is what they did," he said.
Five women and four military deserters were among those killed in Sunday's attack, said the Observatory.
The clashes had erupted just as the UN Security Council was holding an emergency session that condemned Syria's government for using artillery in a massacre that killed at least 108 people in the town of Houla.
On Monday, an activist in Hama told AFP by telephone that "Hama is like a ghost town."
"We are very afraid now, because the regime troops are surrounding the areas where there was fighting, and we fear there might be a new attack," the activist added.
The Syrian National Council, the country's main opposition bloc, said many Hama residents had fled the city during Sunday's violence, and that there was a lack of medicine to treat the injured.
The killings came two days after 108 people were killed and 300 injured in Houla, in central Homs province.
UN officials told the emergency Security Council meeting on the slaughter that the dead included at least 49 children.
The Houla massacre sparked international outrage and condemnation, while protesters across Syria took to the streets to condemn the killing.
The Observatory's updated toll bought the number of people killed across the country on Sunday to 87.
There are now more than 280 unarmed military observers in Syria to monitor a cessation of hostilities that started officially on April 12 but lurches closer to collapse each day.
UN-Arab League envoy Kofi Annan is to arrive in Damascus Monday, before briefing the Security Council on Wednesday on his efforts to end the 15-month crisis.
More than 13,000 people have been killed in Syria since an anti-regime revolt broke out in March 2011, according to the Observatory.