BEIRUT (Reuters) - Two explosions struck the heart of Damascus on Saturday, killing at least 27 people in an attack on security installations that state television blamed on "terrorists" seeking to oust Syrian President Bashar al-Assad.
Cars packed with explosives targeted the criminal police headquarters and an air security intelligence centre at 7.30 a.m. (0530 GMT), television said, shredding the facade of one building and sending debris flying through the streets.
Gruesome images from the sites showed what appeared to be smoldering bodies in two separate vehicles, a wrecked minivan smeared with blood, and severed limbs collected in sacks.
At least 27 people were killed and 140 wounded, an interior ministry statement said.
"We heard a huge explosion. At that moment the doors in our house were blown out ... even though we were some distance from the blast," said one elderly man, his head wrapped in a bandage.
No one claimed responsibility for the detonations, which followed a series of suicide attacks that have struck Damascus and Syria's second city Aleppo over the past three months.
The explosions came two days after the first anniversary of the uprising, in which more than 8,000 people have been killed and about 230,000 forced to flee their homes, according to United Nations figures.
They also coincided with a joint mission by the Syrian government, the United Nations and the Organization of Islamic Cooperation that was due to start assessing humanitarian needs in towns across Syria which have suffered from months of unrest.
One source involved in the mission said team members were still gathering in Syria and it was not immediately clear if they would begin their work this weekend as previously planned.
Violence was reported elsewhere in Syria on Saturday.
The British-based Syrian Observatory for Human Rights, which has a network of contacts within Syria, said the body of an old man was found on Saturday, a day after he was arrested during raids in the northern region Jabal al-Zawiyah.
It added that five people died in the eastern town of Raqqa, including three who were wounded a day earlier. One person was shot dead by security forces during the funeral of two people killed on Friday.
The Avaaz campaign group said it had evidence of 32 children being tortured last week in the central city of Homs, posting footage on the Internet of the infants in hospital. It said some had broken bones, badly cut fingers and gunshot wounds.
Syria denies accusations of brutality and says it is grappling with a foreign-backed insurgency. Reports from the country cannot be independently verified as authorities have barred outside rights groups and journalists.
The U.N.-Arab League envoy for Syria, Kofi Annan, warned on Friday that the crisis could spill over into neighboring countries and urged international powers to lay aside their differences and back his peace initiative.
While the West and much of the Arab world have lined up to demand that Assad steps down, his allies Russia, China and Iran have defended him and cautioned against outside interference.
"The stronger and more unified your message, the better chance we have of shifting the dynamics of the conflict," an envoy said, summarizing Annan's remarks to a closed-door meeting of the 15-nation Security Council.
Turkey said on Friday it might set up a "buffer zone" inside Syria to protect refugees fleeing Assad's forces, raising the prospect of foreign intervention in the revolt, although Ankara made clear it would not move without international backing.
Diplomats have said that without a swift resolution, Syria will descend into a full-blown civil war.
Syria lies in a pivotal position within the Middle East, bordering Turkey, Jordan, Israel, Iraq and Lebanon, and its 23-million-strong population comprises a combustible mix of faiths, sects and ethnic groups.
"I think that we need to handle the situation in Syria very, very carefully," Annan told reporters in Geneva on Friday.
"Yes, we tend to focus on Syria but any miscalculation that leads to major escalation will have impact in the region which would be extremely difficult to manage," he said.
Al Qaeda leader Ayman al-Zawahri, in a video recording posted on the Internet last month, urged Muslims around the region to help Syrian rebels. Syria has previously blamed al Qaeda for at least some attacks on its territory and has vowed to respond with an iron fist.
Annan presented Assad with a six-point peace proposal at talks in Damascus last weekend. Envoys said he told the Security Council on Friday that the response to date was disappointing.
Assad insists the Syrian opposition stop fighting first, while the United States, Gulf Arabs and Europeans have demanded that Assad and his much stronger forces make the first move. Russia wants both sides to stop shooting simultaneously.
Annan will send a team to Damascus early next week to discuss a proposal to deploy international monitors in the country, his spokesman Ahmad Fawzi has said.
Writing by Crispian Balmer; Editing by Mark Heinrich