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A top Syrian rebel military leader was wounded and perhaps killed by a bomb stuck to his car, activists said on Monday.

The Britain-based Syrian Observatory for Human Rights said the blast targeted Col. Riad al-Asaad during a visit to the town of Mayadeen in eastern Syria.

The Observatory cited conflicting reports on al-Asaad's fate, with some saying he had been killed and others saying he lost a leg. There was no immediate claim of responsibility for the attack.

Al-Asaad is a prominent defector from the Syrian military who became head of the Free Syrian Army, an umbrella group that tried to gather rebel fighters under a unified command.

But al-Asaad became little more than a figurehead and his group has been superseded by the Office of the Chiefs of Staff, associated with the opposition Syrian National Coalition and led by Gen. Salim Idris. That body, too, has failed to project widespread authority inside Syria, where most groups cobble together their own funding and arms.

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    Meanwhile, a series of mortar strikes near a downtown Damascus traffic circle killed one person and wounded several others, the government-run Ikhbariyeh TV station reported.

    Umayyad Square, at the center of a large intersection west of downtown, sits near the government TV headquarters, the Sheraton hotel and a number of faculties of the University of Damascus.

    Syria's state news agency reported no dead and at least six wounded in the strikes, which it said hit near the Opera House.

    It was unclear who was behind that attack as well, reflecting the often chaotic nature of Syria's two-year-old civil war pitting hundreds of independent rebels groups against the forces of President Bashar Assad. The U.N. says more than 70,000 people have been killed since the conflict began with political protests in March, 2011.

    Such sporadic strikes on Damascus have grown more common in recent weeks and often appear to target government buildings. Most cause only material damage, but spread fear in Damascus that the city, which has so far managed to avoid the widespread clashes that have destroyed other cities, could soon face the same fate.

    Damascus residents reported hearing intensive shelling on Monday, though it was hard to tell where it was coming from.