At least six people died this morning when a suicide bomber riding a motorbike slammed into a military bus in a ball of fire and smoke in the Pakistani garrison city of Rawalpindi. At least 20 were injured in the attack, which occurred in a crowded market area during rush hour, BBC reports. Nobody has claimed responsibility for the attack, but authorities have blamed Taliban militants based near the Afghan border.
                                    
                                    
                                
                                
                             
                            
                            
                            
                            
                            
                                
                                
                                    
                                        Rawalpindi has recently become a hotspot for such attacks. Opposition leader Benazir Bhutto was assassinated here, and two other suicide attacks last fall—one of them also targeting a crowded military bus—were blamed on a tribal warlord with links to al-Qaeda.