A Syrian protester gestures as he is silhouetted behind a Syrian flag bearing Arabic writing that reads:"God," during a demonstration demanding that Syria's President Bashar Assad steps down, in front of the Syrian Embassy in Amman, Jordan, Sunday, May 22, 2011. (AP Photo/Nader Daoud)
(AP) BEIRUT - Rebels seeking to topple Syrian President Bashar Assad killed three regime officers in separate attacks Tuesday around Damascus, activists and state media said, the latest violence targeting the security forces used by the government to quash dissent.
A bomb hidden in an army truck also exploded in the capital, wounding several people.
The persistent bloodshed has tarnished efforts by a U.N. team of observers to salvage a truce that started to unravel almost as soon as it began on April 12. Despite the violence, the international community still sees the peace plan as the last chance to prevent the country from falling into civil war — in part because there are no real alternatives.
U.N. monitors visited the restive Damascus suburb of Douma on Tuesday, their second visit in two days. Activist Mohammed Saeed said shelling and gunfire in the area Tuesday killed one person. Amateur videos posted online showed smoke rising into the sky after an explosion as well as tanks moving through the streets alongside soldiers firing weapons.
The observers also returned to the central city of Hama, where regime forces killed more than 30 people on Monday. The killings were apparently in retaliation for a large rally to welcome the team during a visit on Sunday.
An amateur video showed two women appealing to the team's head, Col. Ahmed Himiche, for protection.
"They slaughtered us! Our children are gone! Burning and killing and slaughter!" one woman yells, preventing Himiche from shutting the door of the white U.N. Land Cruiser. "If you really came as observers for us, have mercy on us!"
Another video shows residents running for cover as men who appear to be soldiers walk across a nearby rooftop behind a wall of sandbags.
Team spokesman Neeraj Singh said the team also visited the city of Homs, where two observers are staying, and that two would remain in Hama.
The Britain-based Syrian Observatory for Human Rights said an intelligence officer was shot dead in the northeastern Barzeh neighborhood of the capital Damascus. Also Tuesday, the state news service said "terrorists" shot to death a retired lieutenant colonel and his brother, a chief warrant officer, in an area southwest of the capital.
Inside the city, explosives planted in an army truck blew up as the vehicle traveled through downtown, leaving a hole in its roof and blood and shattered glass on the road. The truck's driver and two passengers in a nearby car were injured and taken to a hospital.
The state news service said an "armed terrorist group" planted explosives under the driver's side.
No one immediately claimed responsibility for the attacks.
The 11-person U.N. team is in Syria to observe the cease-fire and prepare for a total of 300 monitors to arrive later.
Tuesday's attacks underlined the increasing militarization of the conflict, which began in March 2011 as peaceful protests calling for political reforms with inspiration from successful revolts in Egypt and Tunisia. The government cracked down with massive force, deploying troops, snipers and pro-government thugs against the opposition, while regime opponents armed themselves for protection and joined forces with army defectors.
The U.N. says more than 9,000 people have been killed since the Syrian conflict began.