Thousands of anti-government protestors Friday took to the streets of Syrian cities, calling for freedom and reform, while armed groups shot indiscriminately at the demonstrators, killing at least six people, including an officer, the state TV reported.

The "saboteurs" cut off a road and set tyres on fire in a suburb of the Syrian capital of Damascus, said the TV, adding that another armed group opened fire at the demonstrations in the central province of Homs, killing one people and wounding dozens others.

However, the Doha-based Al-Jazeera TV quoted activists as reporting that at least 13 people were killed nationwide, as thousands of anti-government protestors hit the streets on Friday after Muslims' noon prayers in several towns and cities across Syria, including Homs, Hama, Daraa, Der al-Zour, calling for freedom and the downfall of the leadership.

The Syrian government said 500 members of the security forces have died since the eruption of the protests in mid March, including 120 who died last week in northern Syria, while, according to activists, more than 1,400 civilians died and some 10, 000 were detained during the government's alleged crackdown on protests.

Meanwhile, a Syrian military source said Friday that the army units had been deployed in all villages in the northwestern town of Jisr al-Shughour along the border with Turkey, and called on people, who were forcibly displaced from their homes by the armed groups, to return after security was restored.

The unrest in Syria aroused international condemnation for the alleged crackdown on protestors by the Syrian security forces. On Thursday, the European Union announced a third round of sanctions targeting the Syrian leadership, and U.S. Secretary of State Hillary Clinton urged Damascus to pull its troops back from the Turkish border.

Syria has been gripped by more than three months of anti- government protests, during which the protestors' demands have snowballed from modest reforms to the downfall of the leadership who has ruled the country for about four decades.

Syrian President Bashar al-Assad has responded to the country's unprecedented anti-government protests by offering some concessions, including lifting the state of emergency in place since 1963, releasing hundreds of political detainees and reshuffling the government.

Syria blames the unrest on "armed extremist groups" which aim at toppling Syrian President Bashar al-Assad and establishing an Islamic emirate instead.