Several people were killed or injured Wednesday when rebels fired mortar shells at a refinery in central Syria and a bus in the capital Damascus, local media reported.

Several workers were wounded when the rebels fired multiple mortar shells at the main oil refinery in the central province of Homs, the state-run SANA news agency reported. It said the " terrorist" attack also damaged one of the oil tankers at the refinery.

Homs is now the center of the government troops' attention as they are fighting furious battles against the western-backed rebels, mainly in the al-Khalidieh and Joret al-Shaiah districts.

Homs Refinery Company was the first refinery in Syria which came into operation in 1959 with a capacity of one million ton per year of light crude oil.

The rebels have targeted several oil and gas pipelines across the country in a bid to paralyze the energy sector of the war-torn country.

In the capital Damascus, meanwhile, several people were reported killed and others wounded when mortar shells struck their bus in the northern district of Barzeh, according to the pro- government Sham FM radio.

The report gave no exact figure about the number of casualties in the bus attack.

On the opposition side, the activists' Local Coordination Committees said that the government troops' airstrike against al- Arbaeen area in Idlib wounded many people.

According to the United Nations report, more than 100,000 people had been killed in Syria's 28-month crisis, with about 1.7 million forced to seek refuge in neighboring countries.