WASHINGTON (CNN) -- Sen. Al Franken said Sunday President Donald Trump's references to Sen. Elizabeth Warren as "Pocahontas" are "racist."

His comments came after Trump reportedly attacked Warren in a closed-door meeting with several senators, telling the Democrats who attended that "Pocahontas is now the face of your party."

Franken, a Minnesota Democrat, said he heard about Trump's remarks from two of his colleagues after the meeting.

"I would have said something," Franken told CNN's Jake Tapper on "State of the Union," pointing to his position on the Senate Indian Affairs Committee.

"I'd have said, 'Mr. President, with all due respect, that's racist. Please stop doing that. I am on Indian Affairs. This is completely unacceptable. You really should stop doing that. It doesn't serve anybody.' Something like that," he said.

Warren was banned from speaking on the Senate floor last week after Republicans said she violated a rule against impugning a colleague by reading a letter from Coretta Scott King. King's letter from 1986 had opposed Jeff Sessions' appointment to a federal judgeship. Sessions later became an Alabama senator and was approved last week to become Trump's attorney general.

The attack stems from Harvard Law School touting Warren as a "Native American" because she had listed herself as a minority in an Association of American Law Schools directory.