At least 30 people were killed in overnight fighting between supporters and opponents of Syrian President Bashar Assad, activists said Monday, warning of a potential civil war in the country.
The clashes erupted in the central city of Homs after two supporters of Assad were kidnapped and killed by anonymous gunmen, according to the Syrian Observatory of Human Rights.
"This infighting represents a serious shift and could be a sign of a coming civil war," it added.
Al-Arabiya broadcaster, however, quoted unidentified witnesses as claiming that the 30 people had been killed by security forces.
On Sunday night, supporters of Bashar, who is facing unprecedented protests, held a massive rally in Damascus to mark the 11th anniversary of his rule.
The event also featured a concert as part of what the official Syrian Press Agency SANA termed the "Festival of Gratitude to the Nation".
The Interior Ministry said on Monday it would use all "forms of firmness" against what it branded terror groups of masked gunmen.
It accused them of jeopardizing national security, according to SANA.
Meanwhile, Qatar has indefinitely closed its embassy in Damascus after pro-government Syrians attacked the building housing it, a Syrian newspaper reported Monday.
"Members of the Qatari diplomatic mission have informed us that work in the embassy is suspended," a Syrian employee at the embassy told the semi-official newspaper Al Watan.
"They have also informed us that all diplomats of the embassy and its consular affairs section will leave for Qatar," he added.
There was no immediate official confirmation from either country.
Last week, government supporters threw stones, eggs and tomatoes at the Qatari embassy in protest against the Doha-based news broadcaster Al Jazeera's coverage of the unrest in the country. No casualties were reported.
Syria has been gripped by pro-democracy protests since mid-March in which more than 1,400 people have been killed, according to human rights advocates.
Such reports are hard to verify as the Syrian authorities have barred most foreign media and international human rights groups from entering the country.
