U.S. Republican senators warned President Donald Trump on Sunday against trying to shut down the federal probe of Russian meddling in the 2016 presidential election, saying it was important to let Special Counsel Robert Mueller do his job.

Trump, a Republican, has renewed his Twitter attacks on both the Federal Bureau of Investigation and Mueller's probe since the firing on Friday of the bureau's former deputy director, Andrew McCabe, days before he was eligible to retire with a full pension.

Republican Sen. Jeff Flake, who has criticized Trump harshly, said it appeared the president's latest comments were aimed at the firing of Mueller.