Appearing Tuesday morning on the Fox Business Network, Sen. Chuck Grassley (R-IA) issued a stern warning to President Trump over his recent tirades against the FBI and Special Counsel Robert Mueller.

The president has reportedly been fuming over the news that his personal lawyer Michael Cohen’s home and office were raided Monday by the FBI—based on a tip passed along from Mueller’s investigation. Trump described the raid, and the ongoing Mueller probe, as “a disgraceful situation” and “an attack on our country.”

“I have confidence in Mueller, the president ought to have confidence in Mueller,” Grassley said Tuesday morning, “and I think it would be suicide for the president to want to talk about firing Mueller.”

Grassley offered some unsolicited advice to Trump on how best to navigate the situation: “The less the president says on this whole thing, the better off he would be, the stronger his presidency would be.”