ABUJA, July 4 (Reuters) - Gunmen attacked an oil rig in the Niger Delta in southern Nigeria on Thursday and kidnapped five foreigners, police said without giving any further details. Two security sources said the rig, located at Soku in Rivers state, is operated by Royal Dutch Shell <RDSa.L>. A Shell spokesman declined to comment. It was not immediately clear if the rebel group MEND, which has just called off a one-month truce, was involved in the attack.
