<br/>U.S. President Barack Obama has warned after the Uganda bombings that groups like Shebab and Al-Qaeda saw Africa as a place where life was cheap and innocents could be killed for little political cost. In an interview with the South African Broadcasting Corporation today, Mr. Obama, who is of African descent, took aim at the motivations of extremists who are increasingly active on the continent. President Obama's interview marked the first, direct, comments by the president on the bombings in Kampala, which sowed death among crowds watching footage of the World Cup final on Sunday, killing 76 people.