Syrian troops and rebels clashed on Sunday in the countryside of Damascus province and near the northern city of Aleppo, the Syrian Observatory for Human Rights reported.
Opposition fighters attacked regime forces overnight at a checkpoint in Damascus province near the border with Lebanon, the Britain-based watchdog said.
And in Aleppo, violent clashes broke out between the army and rebel forces in at least two villages, the monitoring group reported, without reporting casualties.
But a civilian was killed in shelling of Antareb, a town in Aleppo province near Idlib where rebel forces are concentrated. And another civilian was killed in bombing of Kafr Sita town in the central province of Hama.
In Douma, near the capital, activist and doctor Adnan Wehbeh was shot dead in front of his clinic, the Observatory said, blaming security forces for what it said was an assassination.
The Observatory also reported that a convoy of 45 tanks and armoured vehicles transporting soldiers was seen heading east on the Palmyra-Deir Ezzor road.
In the northwest province of Ar-Raqqah, hundreds of people took part on Sunday in the funeral of a man killed the previous day in bombardment of the town of Tabka, according to the group.
And at a funeral in Damascus province, it said, thousands of mourners chanted anti-regime slogans at the funeral of a man killed by sniper fire in the town of Irbin.
On Saturday, violence in Syria killed 89 people, including 57 soldiers, the largest number of casualties the military has suffered in a single day since an uprising began in March 2011, the watchdog said.
The Observatory's head Rami Abdel-Rahman explained that regular troops were fighting in unfamiliar territory.
"What exacerbates those losses is that the army is fighting locals of those towns and villages, whether military defectors or civilians who took up arms against the regime, who know the area inside out and enjoy public support."
The Observatory says as many as 2,400 of the more than 13,500 people killed in Syria since the uprising erupted in March 2011 have died since a UN-backed ceasefire began on April 12.