U.S. Sen. Sherrod Brown (D-OH) pauses during a news conference on currency and trade February 10, 2015 on Capitol Hill in Washington, D.C.
Washington CNN —  

President Barack Obama’s barbs at Sen. Elizabeth Warren on trade have been “disrespectful” and driven by gender, Sen. Sherrod Brown said Tuesday.

That prompted an indignant response from the White House, which said it was expecting an apology from the Ohio Democrat.

Brown was defending Warren in the wake of Senate Democrats’ move to block Obama’s free trade initiative – the President’s biggest legislative priority in his last two years and potentially a legacy-making effort.

The battle has pitted Obama against Warren, a Massachusetts liberal who has led the left’s campaign against the 12-country Trans-Pacific Partnership. In an interview over the weekend, Obama said Warren has been “absolutely wrong” in her critique of the deal – which the United States, Japan, Canada, Mexico and other Pacific Rim countries are still negotiating.

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“The truth of the matter is that Elizabeth is, you know, a politician like everybody else,” Obama told Yahoo News. “And you know, she’s got a voice that she wants to get out there. And I understand that. And on most issues, she and I deeply agree. On this one, though, her arguments don’t stand the test of fact and scrutiny.”

After Democrats led a Senate vote to block consideration of a bill that would allow Obama to fast-track that deal without amendments, Brown said Obama had gotten “more personal” than he should have in critiquing Warren, according to a Politico account of his comments.

He said Obama used Warren’s first name “when he might not have done that for a male senator, perhaps?”

“I think the President was disrespectful to her by the way he did that,” he said. “I think that the President has made this more personal than he needed to.”

The White House on Wednesday called the remarks off-base, noting that Obama often uses lawmakers’ first names. And they suggested that Brown owes the President an apology.

“There are a number of instances where the President has used the first name of the senator to reference them in public, both men and women, including multiple instances in which he’s referred to Sherrod Brown as Sherrod in public setting,” White House press secretary Josh Earnest said.

“I believe that Sen. Brown, given the opportunity to consider his remarks, will then offer up an apology because he’s a stand-up guy,” he said.

As of midday Wednesday, Brown’s office said the senator had not apologized to Obama.

“Sen. Brown believes that this debate shouldn’t be personal, but about getting best possible deal for American workers and American manufacturers,” one of his aides said.

On Tuesday, Brown also swung back against Obama’s argument that Democrats are too busy thinking of the new deal as an expansion of the North American Free Trade Agreement – which didn’t include the labor and environmental provisions that his negotiators are seeking in the Trans-Pacific Partnership.

“When he said that a number of us, not just Sen. Warren, but don’t know what we’re talking about, we’re fighting the last war, a number of those phrases he used, I assume he wished he hadn’t said them because he shouldn’t have said them,” Brown said.

“I’m not going to get into more details,” he said. “I think referring to her as first name, when he might not have done that for a male senator, perhaps? I’ve said enough.”

It’s not the first time Brown has accused Obama of making personal attacks. He made a similar statement last week as Obama visited Nike in Oregon to make his trade pitch.

“American workers have seen the effects of unfair foreign trade on their jobs and manufacturing facilities – they don’t need their elected leaders making personal attacks on each other during an important policy debate,” Brown said then.

CNN’s Jim Acosta and Kevin Liptak contributed to this report.