Three suicide car bombers, among them a woman, killed themselves and three companions at a police checkpoint outside Somalia's government base of Baidoa, a senior official and a police officer said Thursday. «Three cars have arrived at government checkpoint and as the police tried to check them, they exploded,» Deputy Defense Minister Salad Ali Jelle told The Associated Press. «The three drivers were killed on the spot and three others who were with them,» the minister said by telephone. «We have captured three who were with them who have tried to flee. The dead include non-Somalis, they are al-Qaida supporters.» A female suicide bomber detonated herself in one of the vehicles, said a police officer on condition of anonymity because he was not authorized to speak to the media. He said four civilians were taken to a Baidoa hospital.