President Trump slammed the "rigged system" Friday morning following news that former FBI Director James Comey prepared an exoneration statement in the bureau's investigation into Hillary Clinton's use of a private email server before the FBI interviewed Clinton and several of her close aides.

"Wow, looks like James Comey exonerated Hillary Clinton long before the investigation was over...and so much more. A rigged system!" Trump tweeted Friday.

Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, and Judiciary Subcommittee Chairman Lindsey Graham, R-S.C., sent a letter to the FBI on Thursday asking for records related to the draft exoneration statement.

The two Republican senators said they learned the former FBI director had worked on a statement exonerating Clinton starting in April or early May from transcripts of interviews the Office of Special Counsel conducted with two FBI officials who worked with Comey during his time as director of the bureau.

In a second tweet, the president also praised the first responders and law enforcement working in southeastern Texas, and said the situation is improving but recognized there is "so much to do."

"Texas is heeling fast thanks to all of the great men & women who have been working so hard. But still, so much to do. Will be back tomorrow!" Trump tweeted Friday morning, misspelling "healing."

The president later deleted that tweet and, in a subsequent version, corrected the spelling of the word "healing."

The White House said Thursday that Trump would return to Texas on Saturday and also visit Louisiana, which was hit by Harvey.

Trump may visit the Houston area depending on conditions, as well as Lake Charles, La.