(CNN) -- Syrian forces shelled the country's western city of Al-Rastan, just north of Homs, for a second consecutive day Wednesday in a battle against military defectors, opposition activist groups reported.
Syrian jets supported government ground forces in an attack on the city intended to put down a revolt challenging President Bashar al-Assad's hold on power, said the Local Coordination Committees of Syria -- a network of opposition activists who organize and document anti-government demonstrations.
The Syrian army was fighting units that had defected from the military, said the LCC and the Syrian Observatory for Human Rights, a London-based opposition group.
In eastern neighborhoods of Homs, a series of bombs exploded Wednesday night, said Omar Edelbi, an LCC spokesman.
Five civilians and four military defectors were killed in Al-Rastan, said Rami Abdul Rahman, head of the observatory. Nationwide, the death toll was 17, the group said, citing another five in Homs, two in Daraa and one in Banias, he said.
But the spokesman for the LCC said 16 civilians were killed Wednesday by Syrian security forces, 14 of them in Homs alone and the other two in Daraa.
The state-run Syrian Arab News Agency reported that 10 military personnel were buried Wednesday.
Fighting also occurred in other parts of western Syria on Wednesday, according to rights groups and government reports.
State media said a nuclear engineering specialist was killed near the Baba Amr section of Homs after being gunned down by "an armed terrorist group."
A law enforcement officer was killed Tuesday in the western town of Hama after being gunned down by an unidentified terrorist group, according to the state-run Syrian Arab News Agency.
Meanwhile, rights groups said two people died after they were taken into custody at a military checkpoint in Homs, the Syrian Observatory for Human Rights said.
The Syrian government has been battling opposition activists, saying it is engaged in a campaign against terrorists.
Almost 3,000 people have died in the government's crackdown, according to some accounts.
CNN is unable to independently confirm death tolls or events in Syria, which has restricted access to many parts of the country by international journalists.