WASHINGTON (Reuters) - U.S. Olympic swimmer Ryan Lochte, who has apologized for an "exaggerated" story about being robbed at gunpoint at the Rio Games, will be summoned to testify before Brazil's Justice Department, Fox News reported on Thursday.

If Lochte declines to attend, there would be no penalty, but he would not be able to engage in a plea deal, Fox said, citing comments by Detective Clemente Braune.

(Reporting by Timothy Ahmann)