Syria's air force staged new strikes Wednesday on several rebel-held areas across the country, including Raqa in the north, Homs in the centre and Damascus province, a monitoring group said.
The organisation also reported the seizure of an air defence base by rebel forces in the southern province of Daraa.
"New air raids struck the city of Raqa," said the Syrian Observatory for Human Rights, three weeks after rebels seized total control of the provincial capital.
Amateur video filmed by activists and distributed online showed an area identified as the city's Bedouin neighbourhood mostly reduced to rubble, as a cameraman was heard blaming an air strike.
"Civilians have been targeted," said the unnamed cameraman, as a siren sounded.
The city has been the target of frequent air strikes since the pullout of troops from the first major city to have fallen out of regime control in Syria's conflict, which the UN says has killed more than 70,000 people in two years.
Warplanes also targeted the edges of the village of Abel in the central province of Homs, said the Observatory, which relies on a broad network of activists, doctors and lawyers for its reports.
In Daraa, rebels seized the headquarters of an air defence brigade after the withdrawal of regime troops.
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Video posted on the YouTube website by Syrian activists showed opposition fighters milling around the base, examining a damaged rocket.
"This is military base 49, liberated by the heroes of the Free Syrian Army," one says.
Meanwhile, clashes pitting rebels against troops raged in Joussiyeh, in a restive area near the Lebanese border, the Britain-based watchdog added.
And in Damascus province, warplanes carried out three air strikes on Ziabiyeh and another on Mleiha, the Observatory said, without elaborating on casualties.
Fresh battles were also reported in several flashpoints on the outskirts of the capital, as a military source loyal to President Bashar al-Assad's regime pledged that Damascus "will remain secure", according to a pro-regime newspaper.
"We have warned the terrorist groups again and again... that if they come anywhere near Damascus it will mean certain death both for them and for their leaders," an unnamed military official told Al-Watan.
"The army and all its units are ready to defend Damascus, which has not and will not be desecrated by the terrorists... Damascus is safe and it will remain safe," he said.
According to a preliminary toll by the Observatory, at least 88 people were killed in violence throughout Syria on Wednesday.