DAMASCUS - Twin car bombs targeting security posts in Syria’s second city of Aleppo killed at least 28 people on Friday, state media said, as rebels accused the regime of carrying out the attacks as a diversion.

The explosions came as tank-backed troops advanced on pockets of resistance in the battered protest hub of Homs, and as heavy security deployments nationwide thwarted planned protests against key regime ally Russia. The powerful mid-morning blasts ripped through the northern commercial hub, also wounding 235 people, said state television, which broadcast gruesome footage. Mangled bodies were shown in pools of blood outside rows of shattered buildings and piles of rubble strewn across a broad avenue.

State television called the bombings, the first in Aleppo since the uprising against President Bashar al-Assad’s regime erupted almost a year ago, the work of “armed terrorist gangs.”

It said a “suicide bomber in a car packed with explosives” attacked a police station, flattening a nearby food distribution centre. The second bomb targeted an intelligence base. But the rebel Free Syrian Army said the government itself was behind the attacks, hoping to divert attention from its military operations against civilians in the besieged protest city of Homs.

Saudi King Abdullah said world confidence in the United Nations had been “shaken” after Russia and China vetoed a resolution condemning the Assad regime’s crackdown on dissent.

In Geneva, the UN rights office said Syrian officials responsible for carrying out or ordering crimes against humanity should face prosecution by the International Criminal Court. Despite mounting calls for military aid to outgunned and outnumbered rebels in Syria, Arab and Western governments have so far resisted such a possibility. But the opposition Syrian National Council said it expects to be recognised by several Arab states within days. So far only post-revolt Libya has recognise the umbrella group as its sole Syrian interlocutor.

Meanwhile, the Arab League is likely to launch a “Friends of Syria” coalition and appoint a special envoy to the country at a meeting this weekend, a Western diplomat said Friday.

The diplomat also said that Iranians were “on the ground” giving technical help to Syrian intelligence services, and warned that President Bashar al-Assad’s regime had “many levels of violence” yet to use.

Meanwhile, Russia on Friday accused the West of being an “accomplice” to the violence in Syria and said the country’s opposition bore full responsibility for ending the ongoing violence.

Deputy Foreign Minister Sergei Ryabkov said that Syrian President Bashar al-Assad’s promise to stage a new constitutional referendum meant that it was now up to the armed resistance movement to take the next step.

He also warned that Russia was ready to follow this month’s veto of a draft UN Security Council resolution on the crisis with additional “strong measures” should the West continue to refuse to acknowledge the opposition’s role in the crisis.

“The Syrian leadership has assured us of its readiness to quickly hold a referendum on a new constitution and move toward elections,” Ryabkov told the ITAR-TASS news agency.