A bomb killed six people and wounded scores on Thursday when it exploded near the Sayeda Zeinab mausoleum in Damascus, Syria's most visited Shiite pilgrimage site, the authorities said.The deadly blast south of the capital came ahead of the annual commemoration of Ashura, when Shiites remember the death of the Imam Hussein, grandson of the Prophet Mohammed, in a seventh century battle.The interior ministry gave a death toll of six, state news agency SANA reported, revising an earlier death toll of five.