Armed pirates raided a tanker off the West African coast and kidnapped 23 sailors today. The International Maritime Bureau, which monitors piracy worldwide, said pirates boarded the tanker as it idled about 62 nautical miles from Benin's capital of Cotonou. Pirates struck as the vessel tried to transfer its cargo to another ship. The bureau said, pirates sailed off with the crew to an unknown location.The attack occurred as another vessel in the same area came under attack from pirates, where the crew was able to lock themselves into a strong room and wait for the attackers to leave.Piracy in the Gulf of Guinea has escalated over the last eight months