The U.S. Secret Service has recommended former president and current Republican Presidential Nominee Donald Trump's campaign stop holding rallies outdoors following the assassination attempt in Butler, Pennsylvania, sources familiar with the matter told ABC News.

While there are rallies planned in the coming days, none are scheduled to be held outdoors. Conversations about upcoming rallies sites have not included any outdoor venues, the sources said.

It comes after U.S. Secret Service Director Kimberly Cheatle, who came under scrutiny for the agency's failure to prevent the assassination attempt on Trump, resigned Tuesday.