KARACHI, Pakistan --Officials say twin bomb attacks against Pakistan navy buses have killed three people and wounded more than 50 others in the country's biggest city. Police say the blasts early Tuesday took place roughly 15 minutes apart in different areas of Karachi. Navy Commander Salman Ali says three people were killed in the attacks. Local government spokeswoman Sharmila Farooqi says the first attack was apparently carried out by a man riding a motorcycle. The buses were taking naval employees to work. Karachi is the capital of southern Sindh province, where the navy's main facilities are located. Islamist militants seeking to overthrow the government or a halt in army offensives against their safe havens in the northwest often attack security forces.