Two Egyptian students at a south Florida university were indicted Friday on federal explosives charges, but prosecutors would not say whether the men planned to carry out an attack or hurt anyone. Ahmed Abdellatif Sherif Mohamed, 24, an engineering graduate student and teaching assistant at the Tampa-based University of South Florida, and engineering student Youssef Samir Megahed, 21, have been held in South Carolina since Aug. 4 when they were stopped for speeding and authorities found explosives in the trunk of their car. They were indicted by a grand jury in Tampa on charges of carrying explosive materials across state lines. Mohammed also faces terrorism-related charges for teaching and demonstrating how to use the explosives. Steve Cole, a spokesman for federal prosecutors in Tampa, declined to talk about what the men may have been planning, if anything.