A Yemeni security official and a tribal leader say two Japanese tourists have been kidnapped in the Marib province east of the country's capital of San'a. The official and the tribal leader say the Japanese were visiting a historic dam in the town of Marib when they were seized by unknown assailants. Both the official and the tribal leader spoke on condition of anonimity because they were not authorized to talk to the media. Marib is located 176 kilometers (109 miles) east of San'a. Last month, a bombing at a military checkpoint in the province killed three Yemeni soldiers and injured four.