CAIRO, May 6 (Reuters) - The United Arab Emirates denied allegations by Sudan that an Emirati drone had been used in an attack on Khartoum airport on Monday launched from Ethiopia, according to a statement by a UAE official late on Tuesday. Sudan has long accused the UAE of backing the paramilitary Rapid Support Forces, which have been fighting the Sudanese army in a three-year-old civil war that has devastated the country. The Gulf state has denied this and said it seeks an end to the conflict, one of the world's deadliest.