At least 27 people have been killed and 97 others wounded in a pair of explosions in Damascus, the Syrian health minister has said.
State television blamed "terrorists" for the Saturday morning explosions and reported that vehicles packed with explosives had been used. The blasts targeted buildings belonging to a customs office and air force intelligence.
Most of the casualties were civilians, state television said. The channel broadcast interviews with Syrians who blamed the attack on the United States and Gulf nations, including Saudi Arabia and Qatar, who they said had sent terrorists.
The attacks come two days after the one-year anniversary of the start of the uprising against Syrian President Bashar al-Assad.
"I woke up to two massive explosions around 7:30 this morning - one was on Baghdad street less than a mile away from my home," a witness in Damascus told Al Jazeera. "Relatives closer to the explosion told me their windows were blown out and doors destroyed from the blast."
Bassma Kodmani, a Paris-based member of the opposition Syrian National Council, said she doubted the armed groups trying to bring Assad down by force have the capacity to carry out such attacks on security institutions in the capital.
"I don't think any of the opposition forces or the Free Syrian Army has the capacity to do such an operation to target these buildings because they are fortresses,'' she said. "They are very well guarded. There is no way anyone can penetrate them without having strong support and complicity from inside the security apparatus."
State-run news agency SANA said a third blast went off near a military bus at the Palestinian refugee camp Yarmouk in Damascus later in the day, killing the two suicide bombers.
No claim of responsibility
It was not the first time bombers have struck in Damascus, the heart of Assad's power base. There were three alleged suicide bombings in the capital between December and January, which the government blamed on al-Qaeda.
"A few weeks ago, we saw security buildings also come under attack [in Aleppo] and the government has been blaming what they are calling 'terrorist groups'," said Al Jazeera's Zeina Khodr, reporting from Beirut.
She said no one had claimed responsibility for Saturday's attacks but that the opposition has in the past blamed the government for "orchestrating" them to bolster its case against alleged terrorists.
In-depth coverage of escalating violence across Syria
"But we also have to remember that US officials have hinted in the past that they believe that al-Qaeda could be involved, could be taking advantage of the security vacuum in that country," Khodr said.
The spectre of al-Qaeda could make Syria's minority populations more nervous about the Sunni-led uprising against Assad, whose government has sought to rally Alawite, Christian and Shia communities to its side.
One of Saturday's blasts happened in al-Qassaa, a predominantly Christian area.
UN Secretary-General Ban Ki-moon condemned the bomb blasts and called for an immediate end to the violence.
"Mr Ban extended his sympathy and condolences to the families of the victims and the people of Syria," a statement from the secretary-general's office said.
Alain Juppe, the French foreign minister, said: "France condemns all acts of terrorism, which cannot be justified under any circumstances."
France has been at the forefront of calls for Assad to quit.
Mohammed Kamel Amr, Egypt's foreign minister, affirmed Cairo's "fixed position against terrorism in any form, regardless of the reasons behind it".
Meanwhile, the Local Co-ordination Committees (LCC), an opposition activist network, said 22 people were killed across the country on Saturday, including eight in the northwestern city of al-Raqqa where security forces reportedly opened fire on a funeral march.
Al-Raqqa saw a rare mass rally against Assad on Friday and activists said several people were killed by gunfire.
Clashes between the military and army defectors were also reported in the city on Saturday. The LCC said security forces had besieged the hospital that admitted most of the injured.