BEIRUT -   Residents of central Damascus said they spent Sunday night without power as rebels fought Syrian troops half a mile from the Old City in the heart of the capital.Long a stronghold of President Bashar al-Assad, central Damascus is increasingly feeling the impact of a slow advance by rebel fighters who control a crescent of suburbs to the east and south of the city. The price of basic commodities has soared and fuel shortages are affecting services."The power went out all over the city including areas that have usually been ok,” said a resident, who asked not to be named for security reasons.She said it was the first time during the 22-month-old uprising that has turned into a civil war that the most central parts of the capital were affected. State news agency SANA quoted the Minister of Electricity Imad Khamis as saying terrorists - a term the government uses for rebels - had attacked a main electricity line, causing the outage.