(CNN) -- Two powerful suicide car bombs shook the seat of Syrian power Friday in a strike the government blamed on terrorists, and opposition forces called the work of the Bashar al-Assad regime.
In incidents carrying "the blueprints of al Qaeda," bombs exploded outside the offices of two security branches in Damascus, the Syrian capital, said the state-run Syrian Arab News Agency, or SANA.
At least 44 people were killed and another 166 wounded. The casualties included security personnel as well as civilians, SANA said.
Another 21 people, including two children, were killed in continuing anti-government protests, according to the Local Coordination Committees of Syria, a network of opposition activists which collects reports from eyewitnesses and protesters.
CNN cannot independently verify the reports. The Syrian government refuses access to international journalists.
Tanks targeted houses in Idlib and in Homs, the epicenter of the uprising, security forces surrounded a neighborhood, the committee said. Heavy gunfire was reported as well as random arrests.
The Damascus attack was the first known report of a car bomb since the uprising began, and it came amid growing fears of a full-blown civil conflict in Syria. Car bombs and roadside bombs have been the weapons of choice for militants in other conflicts, such as Iraq and Afghanistan.
The attacks followed the arrival of an Arab League advance team in the country to discuss the parameters of a pending mission to monitor the violence that has beset Syria in the wake of an uprising against President al-Assad that has killed thousands.
The United States, which has called for al-Assad to step aside and has initiated sanctions against the regime, deplored the bombings, said there "is no justification for terrorism of any kind" and expressed hope that the strike doesn't undermine the Arab League efforts.
"It is crucial that today's attack not impede the critical work of the Arab League monitoring mission to document and deter human rights abuses with the goal of protecting civilians. We hope that this mission will proceed unfettered in an atmosphere of non-violence. The burden is on the regime to cooperate fully and quickly with the monitoring mission," State Department acting spokesman Mark Toner said on Friday.
U.N. Secretary-General Ban Ki-moon expressed grave concern over the violence and said the "Syrian government should fully and speedily implement the peace plan put forward by the League of Arab States."
"I welcome the arrival of the advance team of the Arab League and look forward to the deployment of the full-scale observer mission, which must be given unhindered access," he said.
The Arab League team in Damascus visited the blast sites, a senior Arab League official told CNN.
The bombers targeted the State Security Directorate and another security branch, according to media reports.
Grisly images of body parts strewn across a street near at least one of the explosions were broadcast on state TV. The bombs charred cars and destroyed buildings, according to video from the scene. The video also showed men carrying the wounded in blankets.
"Preliminary investigations indicate that the criminal attack carries the blueprints of al Qaeda," SANA reported.
The two attacks, according the investigations, were carried out by two suicide bombers with a pair of booby-trapped cars, SANA said.
Abdelatif Mohamed, the Arab League administrative assistant accompanying the advance team, said senior Arab League officials were in closed meetings with the Syrian government.
"The effect of the bombings has resonated across Damascus, especially with the horrible images portrayed on state TV. It has not affected the visit and the team is now heading to observe the bomb's site at Security Headquarters," Mohamed said.
Abdelkarim Al Rihawi, the head of the Syrian Human Rights League, called the attack "the work of the Assad regime and a message to the Arab League that the regime is fighting terrorists."
The Free Syrian Army, the rebel force made up of military defectors, has launched strikes against government forces in recent weeks. But Al Rihawi said the rebel army and other opposition forces don't have "the technology used in such a massive bombing." He said at least 32 civilians died.
"We have information that many of the civilians who died in the blast were detained civilians arrested during protests. I expect more bombings in the next days. There is no al Qaeda in Syria and the hallmarks of the bombings in Syria are similar to those in Iraq. The regime is willing to sacrifice anything to portray to the Arab League that they are fighting terrorists."
Mohamed Hamado, a Free Syrian Army lieutenant colonel, told CNN the government staged the strike "to mislead the international community and Arab League."
"The FSA received requests from the Syrian National Council to temporarily ease up on the attacks against the Syrian Army to give a chance to the Arab League observatory mission to conduct its field operation," he said, referring to the political opposition movement.
"The SNC are not fully aware of the cruelty of the Assad regime, we used to be in his army and know his dirty tricks. We will not respect any truce and we are currently in the heavy rain preparing for several operation against the Syrian Army today."
Throughout most of 2011, Syria has been mired in a bloody uprising that began with government crackdown on protesters calling for the end of the al-Assad's regime.
The escalation in violence by al-Assad's security forces against the opposition has earned worldwide condemnation from other entities along with the United States -- most notably from the Arab League, the European Union, and Turkey.
"The Syrian people continue to suffer daily," Toner said. "They deserve a peaceful political transition that begins with respect of their human rights and an immediate end to repression. The United States will continue to support the Syrian people in their struggle for a peaceful transition from dictatorship to democracy."
The Arab League team that arrived in Damascus on Thursday is coordinating logistics for a planned mission to monitor the opposition and Syrian forces.
Al-Assad agreed this week to allow Arab League observers into the country to monitor what opposition groups say is a deadly crackdown on demonstrators. He has insisted security forces are cracking down on armed terrorist gangs.
The observer mission is part of an Arab League initiative that calls for withdrawing the Syrian army and militias from towns, releasing detainees and ending all forms of violence. Syria and the Arab League signed an agreement Monday to allow the observer mission to enter the country.
The senior Arab League official told CNN that the advance team will meet with Syrian officials and prepare for the observers to travel to Syria by Monday. The head of the observer delegation, Lt. Col. Mohamed Al Dabi, will travel to Syria Saturday.
A meeting is scheduled Monday in Cairo where the Arab League is headquartered, with members of the observer mission to discuss details of the operation, said Ibrahim Zafarani of the Arab Doctors Association. Zafarani said he and two Qatari doctors will be traveling to Syria.
"Our mission will be to assess the hospitals and their capabilities to take on patients, document the type of injuries, evaluate hospital staff and the medical assistance and supplies required for the hospitals, especially in the hotspot areas," he said.
The suicide bombings in Damascus come amid a surge of violence this week that claimed hundreds of lives, the opposition Syrian National Council said.
At least 38 people were killed Thursday, according the Local Coordination Committees. Of those, at least 25 were in Homs.
Earlier this week, around 250 people were killed in a 48-hour stretch, most specifically in Homs and in Idlib province in northwestern Syria, according to the opposition Syrian National Council. It said the government has committed "acts of genocide."
Well over 5,000 people have died so far in al-Assad's crackdown on protests that began in March, the United Nations said earlier this month. But scores of deaths have been reported by activists since that figure was released. One global activist group, Avaaz, said on Friday that more than 6,000 people have been killed in the government crackdown, now in its 10th month.
The government said 2,000 of its soldiers and security forces have been killed in the crisis.
CNN's Mohamed Fadel Fahmy and Salma Abdelaziz contributed to this report.