Syrian government supporters protest European Union sanctions in Damascus on Thursday.

Story highlights

NEW: At least 49 people have been killed in the past two days, the opposition says

The opposition says many have been critically wounded in Rastan

The government denies reports that warplanes have attacked Rastan

The Syrian army has been fighting units that had defected from the military

CNN  — 

At least 49 people have been killed across several cities in western Syria during the past two days of fighting between pro- and anti-government forces, an opposition group said Thursday.

Most of the deaths have occurred in the city of Rastan, where at least 27 people were killed amid heavy shelling, according to the Local Coordination Committees of Syria – a network of opposition activists who organize and document anti-government demonstrations.

Twelve others were killed in the western city of Homs, the group reported.

The Syrian army has been fighting units that had defected from the military, said the LCC and the Syrian Observatory for Human Rights, a London-based opposition group.

Many people have been critically wounded in Rastan, and it is difficult to get them first aid, the Syrian Observatory said.

The Syrian government, meanwhile, says it is engaged in a campaign against terrorists.

It denied reports that warplanes had raided Rastan, according to the government news agency SANA. Instead, it said, law enforcement forces backed by army units confronted “armed terrorist groups” who had wreaked havoc in Rastan and killed civilians.

The government said seven army and law enforcement members had been killed and 32 others wounded.

CNN is unable to independently confirm death tolls or events in Syria, which has restricted the access of international journalists to many parts of the country.

Thursday’s reports from the opposition groups coincide with a mob attack of government supporters in Damascus that U.S. ambassador Robert Ford narrowly avoided, a U.S. government official said.

Ford, who has been outspoken against the Syrian government’s use of violence against protesters, is seen by government supporters as an activist more than a diplomat.

At the time of the attack, Ford was visiting Hassan Abdul Azim, the head of the opposition Arab Socialist Democratic Union.

According to Azim, about 50 to 100 people gathered at the door to his office and began to chant loudly when Ford arrived. Some of them even tried to break down the door, he said.

The crowd protested rowdily for more than two hours, he said.

Azim could not confirm what Ford was attacked with, but he said that tomatoes that had apparently been thrown were cleaned up off the street afterward.