WASHINGTON — President Obama hit back at fellow Democrats who oppose his trade initiatives Tuesday, saying they have their facts wrong.

The president’s blunt words came on the eve of a major Senate committee vote on his trade agenda, which many liberals and labor unions vehemently oppose.

“I would not be doing this trade deal if I did not think it was good for the middle class,” Obama said in an interview with MSNBC. “When you hear folks make a lot of suggestions about how bad this trade deal is, when you dig into the facts, they are wrong.”

Asked particularly about sharp criticisms from Sen. Elizabeth Warren, D-Mass, Obama said: “I love Elizabeth. We’re allies on a whole host of issues. But she’s wrong on this.”

The comments came as major labor unions and business groups clashed over Obama’s bid for “fast-track” authority to advance trade deals being negotiated with numerous nations.

AFL-CIO president Richard Trumka told the Senate Finance Committee that the fast-track legislation would rob Congress of a meaningful role in shaping trade deals.

Fast-track authority lets Congress reject or endorse – but not amend – proposed trade deals backed by the president.

“The idea that fast-track lets Congress set the standards and goals for the TPP is an absolute fiction,” Trumka said, referring to the pending 12-nation Trans-Pacific Partnership.

Obama is likely to send Congress the Pacific-rim proposal if he wins fast-track approval. Trade deals with European nations and others could follow.

Trumka said the Pacific-rim deal “has been under negotiation for more than five years and is essentially complete. Congress cannot set meaningful negotiating objectives in a fast-track bill if the administration has already negotiated most of the key provisions.”

But Chamber of Commerce President Thomas Donohue said fast-track authority is crucial to ratifying deals that would help U.S. producers reach big foreign markets.

Without fast-track, Donohue said, “the United States is relegated to the sidelines as other nations negotiate trade agreements without us, putting American workers, farmers, and companies at a competitive disadvantage.”