Two explosions rocked the Syrian capital of Damascus Saturday killing 27 people and injuring another 140 on the one-year anniversary of the country's uprising, state media reported.

The twin suicide car bombs were aimed at intelligence and security buildings in the capital.

A third blast also was reported, at a refugee camp housing thousands of Palestinians in Damascus, but the two bombers were the only casualties, SANA said.

The attacks occurred in areas where government security is typically high, raising opposition suspicions that the regime of Syrian President Bashar al-Assad was responsible.

The regime blames al Qaeda-linked terrorists for the country's troubles and not citizens seeking reform and democracy.

Opposition forces deny they are involved in the attacks and suggest the bombings are a smokescreen meant to support the regime's justification for using force to end the uprising in what appears to be a violent public relations battle being waged by the government.

Montreal-based Middle East analyst Mohamed Mahmoud said Syrian opposition forces wouldn't have access to that part of the city driving cars laden with bombs because of the security.

He told CTV's News Channel Saturday the explosions carry the same tactical fingerprints as previous bombings in Damascus that began in December, suggesting agents of the regime were likely responsible.

Mahmoud said western intelligence agencies and the Syrian opposition believe the government has links to al Qaeda forces in the country and is using them to help quash the uprising.

Top U.S. intelligence officials also have pointed to al Qaeda in Iraq as the likely culprit behind the previous bombings, raising the possibility its fighters are infiltrating across the border to take advantage of the turmoil.

The bombings hit the air force intelligence department building and the criminal security department, several kilometres apart in Damascus, at approximately the same time, around 7 a.m., the Interior Ministry said.

Much of the facade of the intelligence building appeared to have been ripped away.

Shooting broke out soon after the blasts and sent residents and others who had gathered in the area fleeing, an Associated Press reporter at the scene said.

"All our windows and doors are blown out," said Majed Seibiyah, 29, who lives in the area of one of the blasts "I was sleeping when I heard a sound like an earthquake. I didn't grasp what was happening until I hear screaming in the street."

The last major suicide bombing in Syria happened on Feb. 10, when twin blasts struck security compounds in the government stronghold of Aleppo in northern Syria, killing 28 people.

The UN estimates that more than 8,000 people have been killed since the uprising against Assad began last March.

In recent weeks, Syrian forces have waged a series of heavy offensives against the main strongholds of the opposition -- Homs in central Syria, Idlib in the north and Daraa in the south.

Diplomatic efforts to solve the crisis have yielded no results to date.

UN envoy Kofi Annan told the Security Council in a briefing Friday that he would return to Damascus even though his recent talks with Assad saw no progress in attempts to cobble together peace negotiations between the two sides.

Both Assad and much of the opposition spurned Annan's appeal for talks.

Meanwhile, protests are planned in cities across Canada Saturday afternoon in support of the Syrian opposition and mark the anniversary.

Mahmoud said he's taking part in a demonstration in Montreal, while other events are taking place in cities such as Ottawa and Toronto.

"We want to raise awareness more in Canada and tell our fellow Canadian citizens that what's happening in Syria is a revolution for a people who were under emergency rule for 49 years," he said.

With files from The Associated Press