BEIRUT (Reuters) -- At least 20 Syrian security men were killed when two explosives-laden cars drove into a military camp in the southern town of Deraa on Saturday, an opposition watchdog said, in what appeared to be a double suicide attack by rebel forces.
In a conflicting report, state news agency SANA said three bombs had gone off in the town near the border with Jordan, killing seven people in what it described as a series of terrorist attacks.
Suicide bombings by hardline Islamist militant groups have become a regular feature of the 19-month old uprising against President Bashar Assad, though there were no immediate claims of responsibility for Saturday's attacks in Deraa.
The UK-based opposition Syrian Observatory for Human Rights said the first car had driven into a Deraa military camp and exploded. The casualties were caused by the detonation of the second vehicle which followed it, the Observatory said.
The Syrian state media report did not mention a military target.
It said one bomb had gone off in a busy commercial street.
A second - a car packed with anti-tank mines which did not all explode - was set off near a government office, damaging it and nearby commercial and residential buildings, it said.
The Syrian government routinely blames foreign-backed Islamist militants for the anti-Assad revolt, in which the Observatory says about 38,000 people have been killed.
A suicide bomber killed around 50 members of the Syrian security forces in the province of Hama on Monday, the Observatory reported.