Rep. Adam Schiff (D-CA), the top Democrat on the House Intelligence Committee, urged President Donald Trump Saturday to avoid making statements that would damage his credibility and to stop making “groundless ” accusations.

In his speech for the Democratic weekly address., Schiff brought up the need for Congress to implement an independent commission to investigate Russia’s alleged interference into the 2016 presidential election. Schiff said it would not be an attempt to undermine the President, because only the President can do that.

“As the events of this week demonstrate, an independent commission will be able to conduct its work insulated from any political interference,” he said. “The President believes this investigation as an attempt to undermine his legitimacy or credibility. It is not. Only the President is capable of doing that, and regrettably, he is at great risk of doing so.”

Schiff pointed to Trump’s repeated and unsubstantiated claims that former President Barack Obama had wiretapped Trump Tower during his campaign. Schiff said that repeating such claims or others could “squander” credibility that cannot be regained.

“When a President of the United States makes claims that are proved baseless, it weakens the Presidency and undermines our security and standing in the world. Presidential credibility, once squandered, may never be fully regained,” he said.

Schiff closed by pleading that Trump trust his advisers and that he never make baseless accusations again.

“Seek their counsel. Listen to what they have to say,” he said. “And cherish the trust and hope that was placed in you by virtue of your office, by never again advancing claims that you know – or should know – are simply not true.