Russian and Syrian fighter jets have launched attacks in southern Aleppo province and the Damascus countryside, causing civilian casualties in both locations.
Rebel groups, for their part, made gains south of Damascus and in the eastern Idlib province, activists said on Tuesday.
An Al Jazeera correspondent said hundreds of families were displaced from villages and towns in the southern Aleppo countryside because of heavy bombing by Syrian and Russian fighter jets.
The attacks resulted in civilian casualties and extensive damage to homes and property, the correspondent said.
The developments came amid attacks by President Bashar al-Assad’s military and allied fighters on rebel sites in Burj Sabna, a village in Aleppo’s southern countryside.
An Al Jazeera correspondent said one civilian was killed and several others were wounded in artillery shelling by government forces and allied fighters in Zamalka, Eastern Ghouta and the Damascus countryside, although these areas are part of a so-called de-escalation zone under the Astana agreement.
Activists said a faction of the Union of the Jabal al-Sheikh forces destroyed a government tank in Sahin Hina in western Ghouta, while clashes erupted in the area of Hajar al-Aswad.
Elsewhere, local sources said the Islamic State of Iraq and the Levant (ISIL) group recovered several villages north of the city of Albu Kamal in the eastern suburb of Deir Az Zor, following an attack on government forces.
ISIL, also known as ISIS, is trying to regain momentum and recover some of its lost territories after suffering a string of defeats in both Syria and neighbouring Iraq.
Sham Network reported that Tahrir al-Sham, which controls large swathes of Idlib province, destroyed a government tank in an area east of Idlib city, as well as a military vehicle belonging to another rebel group.
Also on Tuesday, fighting continued in areas connecting the provinces of Idlib and Hama amid Russian attacks from the air, with activists reporting civilian casualties.
The Russian raids targeted al-Mitnaa in the southern countryside of Idlib, the activists said.
Sham Network reported shelling of Amiriya, a town in Homs countryside, and Daraa al-Balad, an area in Daraa city.
In another development, three members of Iran’s Islamic Revolutionary Guard corps’ Fatimiyoon Brigade were killed in clashes in Syria, according to a report carried by Iran’s Tasnim News Agency.
The report said of one of the dead fighters was buried in the Iranian city of Mashhad, while the other two would be buried in Isfahan on Thursday.