June 19 (Reuters) - Iran's Islamic Revolutionary Guard Corps (IRGC) has set up secretive new cells in Iraq to carry out attacks on Gulf countries that host American forces, bypassing established militia networks to avoid detection, eight Iraqi sources told Reuters. Three or four cells, each comprising about 10 elite Iraqi Shi'ite Muslim fighters, launched at least seven drone attacks from desert locations near the southern cities of Basra and Samawa against sites in Kuwait, Saudi Arabia and the United Arab Emirates between April 20 and May 17, three of the sources said.