The planes left Dakar, Senegal, earlier Thursday and were bound for the Moroccan city of Agadir when they came under fire from ground-to-air missiles, the embassy spokesman said. Moroccan government officials said the two planes were fired upon while they were flying at 10,000 feet to 11,000 feet in an international navigation corridor over Bir Moghrein, Mauritania. The embassy spokesman said the second airplane arrived in Sidi Ifni, about 240 miles south of Agadir. The planes were being used by the U.S. Agency for International Development to fight the locust plague in North Africa. The source of the attack was not immediately known and an investigation had been launched, the spokesman said.