By Khaled Yacoub Oweis
AMMAN, March 10 (Reuters) - Syrian Sunni Muslim rebels have launched a counter-offensive to ease an army siege on their strongholds in the central city of Homs, breaking through government lines in the north and west, opposition sources said on Sunday.
Homs, 140 km (88 miles) north of Damascus, lies at a vital road juncture linking army bases on the coast, where a large proportion of President Bashar al-Assad's minority Alawite sect live, and government forces in the capital Damascus.
Both sides have taken heavy casualties since the army went on the attack 10 days ago to take the central districts of Khalidya, al-Qusour and Old Homs, where rebel brigades have been dug in for months, according to opposition military sources.
Fighters based in the provinces of Hama and Idlib advanced on Homs this weekend from the north while brigades from rural Homs attacked government positions in the western Baba Amro district. This was overrun by the army after a long siege a year ago and subsequently visited by President Bashar al-Assad.
Abu Imad, an opposition activist in Homs, said the sound of aerial bombardment on Baba Amro was shaking the city.
"This situation is muddled in the whole of Homs, but what is certain is that the regime is busy trying to repel rebel brigades who have broken into Baba Amro from its rural surroundings," he said.
The official state news agency said "a unit of our brave army engaged with an armed terrorist group that had tried to infiltrate Baba Amro ... and killed and wounded several of its members."
Syrian authorities have banned most independent media from the country.
Home to one of Syria's two oil refineries, Homs is situated amidst rolling hills known before the uprising for producing some of the finest pomegranates and aubergines in the Levant.
The mixed city, inhabited by Sunnis and Alawites, an offshoot of Shi'ite Islam who have dominated Syria since the 1960s, has emerged as a major battleground in the two-year-old uprising against Assad.
Rebels repelled several army attempts to take Khalidya with infantry in the last 10 days and dozens from both sides have been killed, the sources said.
Nader al-Husseini, an activist from Baba Amro, said several roadblocks in the district had fallen to rebel fighters and dozens of loyalist troops and militia had fled to the nearby districts of Jobar and Inshaat.
"For the regime to take hits in Baba Amro is damaging to its morale, especially since Assad visited Baba Amro and was filmed there, supposedly sealing the regime's triumph," Husseini said.
Ahmad al-Tarkawi, an official with the al-Mujahedeen Front, an opposition military group based in central Syria, said rebels had cut a highway linking the north of Homs to the coastal port of Tartus.
He also said that a section of the refinery was on fire after mortars fired by the army overshot their target and hit the facility. (Editing by Stephen Powell)