It was the first significant unrest in the city, which has largely stood by president Bashar al-Assad in the 11-month-old uprising against his rule.
State media claimed that blasts as proof that the regime faces a campaign by terrorists, not a popular uprising against Mr Assad’s rule. The opposition, in turn, accused the regime of trying to smear its movement as government forces try to crush rebels in one of their main strongholds, Homs.
The military, meanwhile, stepped up its siege of Homs that has reportedly killed hundreds over the past week. Soldiers who have been bombarding the central city made their first ground move, storming into one of the most restive neighbourhoods.
At the same time, troops and security forces opened fire on anti-regime protesters who streamed out of mosques after Friday prayers nationwide. The Syrian Observatory for Human Rights said at least 27 civilians were killed.
The morning blasts in the northern city of Aleppo ripped apart the facades of the local headquarters of the Military Intelligence Directorate and a barracks of the Security Preservation forces in another part of the city.
A weeping correspondent on state-run TV showed graphic footage of at least five corpses, collected in sacks and under blankets by the side of the road.
At both sites, suicide bombers in explosive-packed vehicles tried to smash into the entrances, security officials said.
State television cited the health ministry as saying 28 people were killed in the two blasts and 235 wounded, including civilians and military personnel. It didn’t give a breakdown of the casualty toll for each blast.
Captain Ammar al-Wawi, of the Free Syrian Army, a rebel group that wants to bring down the regime by force, denied involvement. He said fighters from his group had a short gunbattle with troops several hundred yards from the Directorate about an hour before the explosion but they did not carry out the bombings. He added: “This explosion is the work of the regime to divert world attention from the crimes it is committing against the people of Homs.”
The blasts were the fourth such dramatic suicide attack since late December. All occurred on Friday mornings against various security headquarters and prompted the same exchange of accusations. The earlier attacks, in the capital Damascus, killed dozens of members of the security forces and civilians, according to Syrian officials. Nobody has claimed responsibility for any of the attacks.
Aleppo has seen only occasional protests. Assad’s opponents have had little success in galvanising support there, in part because business leaders have long traded political freedoms for economic privileges. The city also has a large population of Kurds, who have mostly stayed on the sidelines of the uprising since the Assad regime began giving them long-denied citizenship as a gesture to win support.
Hours after the explosions, hundreds of protesters marched in several Aleppo neighbourhoods after prayers, part of nationwide demonstrations labelled “Friday of Russia is killing our children” – denouncing Russia’s veto last weekend of a UN attempt to condemn Syria’s crackdown.
Regime forces opened fire on the Aleppo protesters, killing at least seven, according to local sources.