DAMASCUS (Reuters) - Two bombs detonated on a central Damascus highway on Saturday, destroying nine cars, residents said, in a further sign that rebels fighting to topple President Bashar al-Assad are shifting tactics towards homemade explosives.
There were no immediate reports of casualties from the blasts from bombs planted under cars on al-Thawra Street, the latest blow to last month's crumbling U.N.-backed truce.
Fifty out of a planned total of 300 United Nations observers are now in Syria to monitor the ceasefire declared on April 12, but their presence has not halted the violence in a 14-month-old revolt that began with peaceful pro-democracy protests.
Deadly blasts have shaken major cities as insurgents seek to even the odds between their outgunned forces and the tanks, artillery and helicopters in Assad's military arsenal.
On April 30, explosions blew the fronts off buildings in the northern town of Idlib, where state TV reported nine people killed and 100 wounded, including security personnel.
Three days earlier, a suicide bomber killed nine, including security men, at a Damascus mosque, the Interior Ministry said.
An Islamist group calling itself the Support Front for the People of the Levant claimed responsibility for that bombing and for an April 24 attack on the Iranian cultural consulate in Damascus. Iran is one of Syria's closest allies.
Assad has long argued that he is combating foreign-backed "armed terrorist groups" rather than a popular uprising. Syrian officials say rebels have killed more than 2,600 soldiers and police. The United Nations estimates that the security forces have killed more than 9,000 people since the rebellion began.