Several Senate Republicans are warning Donald Trump against obstructing justice or pardoning himself, even as they continue to say there's no evidence to support allegations the president's team colluded with Russia in the 2016 elections.

"I'd advise everybody from the president to the people operating the elevator, don't obstruct justice," said Sen. Lindsey Graham of South Carolina, who was one of the House managers of the impeachment proceedings against President Bill Clinton.

Sen. Jerry Moran of Kansas, who voted to impeach Clinton for obstruction, also said presidential obstruction is impeachable. "A president can obstruct justice," he told reporters.