The Syrian troops are fighting "ferocious battles" with armed groups in the northeastern city of al-Raqqa after thousands of rebels poured into the city the previous day, pro-government al-Watan daily said Tuesday.

The armed men have stormed the city from different directions amid reports that intense fighting is currently ongoing there, al-Watan said, adding that the al-Raqqa was one of the safest places in Syria before the rebels' attack.

After the attack, the paper said, the armed men looted houses and government establishment in the city.

On Monday, activists said that the Nusra Front, an offshoot of al-Qaida, stormed large swathes of al-Raqqa, adding that they also took control over several government-owned institutions.

The Britain-based Syrian Observatory for Human Rights posted a video footage on its Facebook page showing a number of government troops taken captive by the armed groups in the city.

It also said Governor of al-Raqqa Hasan Jalili and local head of the ruling Baath party Sulaiman al-Sulaiman were taken captives by the rebels after intense clashes at the governor palace.

The Observatory said that several pro-government people in al- Raqqa had formed an militia to repulse the armed groups' offense on the city.

Other media reports said that the Syrian war jets have pounded several rebel positions in the city, adding that army reinforcements are on their way.

Violence has intensified in Syria recently in what observers described as the escalation before the anticipated pacification after the international community declared support to a political solution to Syria's long-standing conflict.

A recent UN tally placed the overall death toll of Syria's two-year-old conflict at more than 70,000 people.