Damascus bomb one of deadliest of Syrian civil war With the regime also launching indiscriminate attacks on civilian areas in Aleppo, Deraa and Deir Al-Zour in recent days, both from the air and by surface-to-surface missiles, John Kerry, the new US secretary of state, will also be under fresh pressure to strengthen American policy. He will begin an introductory two-week tour of the Middle East on Sunday with officials at loggerheads. American media report that President Obama has vetoed requests by the State Department, the Pentagon and the CIA to allow non-jihadist rebel groups to be armed, but analysts and arms experts claim that new weaponry is being supplied in any case. Some point to a recent influx of anti-tank and anti-aircraft missiles from the Balkans, seen regularly on rebel videos, as evidence that somehow the policy on the ground has already changed, and that US allies such as Qatar and Saudi Arabia have been encouraged to infiltrate arms. The centre of Damascus, which remains solidly in regime hands, is currently under fierce attack from rebel positions in the north, east and south, with one advance reaching within a mile of the historic Old City, one of the oldest continuously occupied settlements on earth. There was no immediate claim of responsibility for Thursday's attack, but Jabhat al-Nusra, which America has proscribed as a terrorist group for its alleged ties to al-Qaeda in Iraq, has admitted to at least seven similar bombings this month alone in the city. The Syrian foreign ministry blamed the bombing on "terrorist" groups linked to al-Qaeda, "that receive financial and logistic help from abroad." Figures for the number of dead ranged from 53 to 59. The latter figure would make it the deadliest attack in Damascus since the start of the uprising two years ago. Among the injured was Nayef Hawatmeh, head of the Palestinian splinter group, the Democratic Front for the Liberation of Palestine. Immediately after the attack, four more missiles hit the city, and eight people were killed by a car bomb in the suburb of Barzah. Some opposition activists claimed that to get through government checkpoints to the city centre the bombers must have been backed by the regime of President Bashar al-Assad. Musab Abu Qatada, head of the rebel Damascus Military Council, said: "The bombing in Al-Mazraa was committed by the regime to cover its crimes, to provide a justification that his crimes are a response to the 'terrorists and extremists'. But the truth is that there is no terrorist or extremist except this criminal regime. He said that the missile attacks were in "retaliation" and hit the headquarters of the army general staff.