Supporters of Pakistani Islamist party celebrate President Pervez Musharraf's resignation in Multan August 19, 2008. Leaders of Pakistan's coalition government set about tackling pressing economic and security problems on Tuesday as a bomb at a hospital in a northwestern town killed 20 people. Coalition leaders were also due to discuss a replacement for Musharraf, the former army chief and key ally of the United States in its campaign against terrorism, who resigned as president on Monday to avoid impeachment.