At least 16 Syrian soldiers have been killed in clashes with rebels in the province of Aleppo, activists say.
The fighting took place in the town of Darat Izza, and at checkpoints outside al-Atarib and Kafr Halab, the Syrian Observatory for Human Rights reported.
On Friday, officials accused rebels of shooting dead 25 men in Darat Izza. Activists said they were militiamen.
Syria has seen escalating violence in recent weeks, with some 116 people reportedly killed on Saturday.
'In a war'
The head of the Observatory, Rami Abdul Rahman, told Agence France-Presse news agency the clashes in Aleppo had taken place simultaneously around dawn, at the end of what he called "one of the bloodiest weeks" since the uprising against President Bashar al-Assad began in March 2011.
"It's like we are in a war," he told the AFP. "Sometimes when two countries are at war, not even 20 people are killed a day. But now in Syria, it has become normal to have 100 killed each day."
The Observatory said 77 civilians died on Saturday, including a family of six in the eastern province of Deir al-Zour, as the military attacked rebel-held areas.
Nineteen solders were also killed, while another 10 troops were shot when they tried to defect to the rebel Free Syrian Army, it added.
The Local Co-ordination Committees, an activist network, put the nationwide death toll on Sunday at 131, including 31 in Deir al-Zour.
The Syrian Arab Red Crescent also said one of its volunteers was shot in the head while on duty in the province and wearing a uniform marked with its emblem. It was not clear who was responsible for the man's death.
Mr Abdul Rahman said at least 644 people had been killed since last Monday.
He said the international community had to reach an agreement on how to resolve the crisis, and criticised the decision of the UN Supervision Mission in Syria (UNSMIS) to suspend its operations because of the violence.
The mission's 298 unarmed military observers and 112 civilian staff are in Syria to verify the implementation of the peace plan negotiated by the UN and Arab League's envoy, Kofi Annan, under which a ceasefire supposedly came into force in April.
"Either go out and observe properly or leave," Mr Abdul Rahman said.
The UN says at least 10,000 people have died since pro-democracy protests began in March 2011. In April, the Syrian government reported that 6,143 Syrian citizens had been killed by "terrorist groups".