Federal authorities said the Indianapolis 500 is an attractive target for terrorists, but there has been no credible or specific threat aimed at the Memorial Day weekend race.

In an internal FBI/Homeland Security Department assessment released Monday to local police, officials said such sporting events, which attract hundreds of thousands of spectators, are attractive potential targets. The assessment said these popular events are inviting to terrorists because of the potential to inflict large numbers of casualties while the whole world is watching.