House Speaker Paul Ryan pledged that Congress will not interfere with Special Counsel Robert Mueller’s investigation into possible coordination between President Donald Trump’s 2016 election campaign and Russia — a probe that has intensified in the last week as Trump campaign officials, including former campaign chairman Paul Manafort, have been indicted.

On Fox News Sunday, Ryan was asked if he could pledge that Mueller’s investigation will not be curbed or stopped.

“We’re not going to interfere with his investigation,” Ryan said. “The investigation will take its course, and we will let it take its course.”

Ryan noted that Trump has “made it clear” he won’t call for Mueller to step down or be fired. The White House has said it will stay out of the way of Mueller’s investigation.

Three House Republicans have said “obvious conflicts of interest” should require Mueller to step down, citing his relationship with former FBI director James Comey, Politico reports.

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Write to Mahita Gajanan at mahita.gajanan@time.com.