Beirut - Syria's air force raided the strife-torn district of Baba Amr in the central city of Homs on Wednesday, four days after rebels infiltrated the neighbourhood that has seen some of the two-year revolt's fiercest battles, a watchdog said.
Clashes also raged near the sensitive Syrian border with Lebanon, said the Syrian Observatory for Human Rights, while the regime's intelligence forces used heavy machinegun fire to target rebel enclaves around the ancient city of Palmyra.
"A warplane carried out a new raid targeting the district of Baba Amr," said the Britain-based Observatory, which relies on a network of activists, doctors and lawyers for its reporting.
Rebels re-entered Baba Amr a year on from the district's fall into army control.
Clashes have raged in parts of the southwestern district of Homs, while rebels in the heart of Syria's third city held out against an escalated army campaign aimed at crushing the insurgency there.
Across Homs, both rebels and troops have sustained heavy losses in the past week, according to the Observatory.
Elsewhere in Homs province, "air force intelligence troops used heavy machinegun fire to target rebels on the outskirts of Palmyra", said the watchdog.
70 000 dead
And on the Syrian border with Lebanon, "four rebel fighters were killed in clashes against troops in the village of Jousiyeh", the Observatory said.
Near the capital, a car bomb exploded near a police station in the Khan al-Sheikh area of Damascus province, the monitoring group said, without elaborating on casualties.
Battles have raged in the area for several days. During the weekend, at least 30 loyalist troops were killed after rebels broke into a military barracks there.
In northwestern Syria, clashes raged at Hish in the province of Idlib, as regime troops "fought to break the [rebel] siege on the Wadi Deif base" nearby, said the watchdog.
Rebels laid siege to Wadi Deif in October.
In Aleppo, in northern Syria, warplanes waged several strikes near Minnigh air base, scene of fierce battles for control since rebels launched an all-out campaign to seize airports in the province on 12 February.
Wednesday's violence came day after at least 110 people were killed across Syria, the Observatory said.
Syria's two-year conflict has left around 70 000 people dead, the UN says.