U.N. observers see Syrian forces kill two: rebels AMMAN (Reuters) - Syrian police killed two people on Tuesday when they opened fire on a crowd who came out to welcome United Nations observers in the eastern province of Deir al-Zor, a rebel official said. As soon as the U.N. convoy entered al-Busaira, a jubilant crowd of hundreds came out to welcome them. It was not minutes before they came under fire," Abu Laila, a Free Syrian Army official, said by phone from the town. The observers immediately left al-Busaira. We called them to come back but they refused," he said, adding that fighting ensued between President Bashar al-Assad's forces and rebels based in the town. There was no independent confirmation of the incident. Another opposition source in the province said that government forces surrounding al-Busaira had begun firing anti-aircraft guns at the town. Government troops have been battling a widening uprising against Assad for 14 months. Al-Busaira is one of many towns and villages under rebel control in Deir al-Zor, a large oil-producing province bordering Iraq, that have been attacked repeatedly in the last four months by government troops trying to regain control. Assad, a member of Syria's Alawite minority, had relied on a network of alliances with Sunni Muslim tribes forged by his late father, Hafez al-Assad, to keep Deir al-Zor under control. But these understandings began breaking down after the province erupted in mass demonstrations in July demanding Assad's removal, and tanks were sent to quell the protest movement. There are 257 unarmed United Nations observers in Syria, sent to enforce an internationally brokered ceasefire that has been regularly violated by Assad's forces and rebels. Reporting by Khaled Yacoub Oweis; Editing by Tim Pearce