DAMASCUS - Three little sisters were killed and another was injured Wednesday when an armed group fired rocket- propelled grenades at a residential area in the central Homs province of Syria, which is witnessing intense clashes between government troops and "armed terrorist groups," the official SANA news agency reported.

"We were standing at our house's doorway when armed groups nesting on nearby schools' rooftops fired rocket-propelled grenades toward our house which led to the killing of my three little sisters while the forth lay in a critical condition at the hospital," Mohammad al-Zoubi, the victims' brother was quoted by SANA as saying.

However, the Doha-based al-Jazeera TV cited activists as saying that the three girls were killed during clashes between the government troops and army defectors. It said 18 people were killed Wednesday in Homs, which has emerged as a hub of anti- government protests over the past seven months.

Sporadic reports of defections have emerged lately, as activists have posted online videos picturing alleged army defectors calling on other fellow soldiers to join what they called the "free Syrian Army," which according to the videos was formed to fight Syrian security forces and the alleged pro-regime gunmen known as "Shabiha" that allegedly attacked and killed opposition protestors.

Neither the activists nor the al-Jazeera accounts could be verified as journalists are banned of independently heading to restive areas.

However, Syria has repeatedly blamed the unrest on armed groups and extremists acting out a foreign conspiracy. Syrian Foreign Minister Walid al-Moallem told a visiting Indian delegation on Wednesday that what is happening in Syria is a result of its supportive stance toward Arab issues mainly the Palestinian question.

The seven-month-old unrest in Syria has claimed the lives of 3, 000 people according to a recent UN tally.