Troops staged a coup in the West African nation of Mauritania on Wednesday, arresting the president and prime minister and shutting down state radio and television, security sources said. President Sidi Ould Cheikh Abdallahi and Prime Minister Yahya Ould Ahmed Waghf had been placed under arrest after troops moved through the capital early Wednesday, security sources and witnesses said. "We are in contact with our embassy to obtain confirmation of the events that appear to be taking place in Nouakchott. Based on initial information, it seems that a group of generals are holding the prime minister," a French foreign ministry spokesman told a foreign news agency in Paris. Mauritania has been facing a political crisis and on Monday 48 MPs walked out on the ruling party less than two weeks after a vote of no confidence in the government prompted a cabinet reshuffle.