MSNBC host Mika Brzezinski lashed out at Ivanka Trump on Twitter on Wednesday for championing equal pay for women even while President Trump halts a rule on salary transparency.

The "Morning Joe" co-host called the first daughter "sad," lamenting that many had hoped she would have been a more vocal advocate for equal-pay policies in the White House.

But no equal pay. Wow. How disappointing. Who represents women in WH? We hoped it would be Ivanka. Sad. https://t.co/bic1xOjkB7 — Mika Brzezinski (@morningmika) August 30, 2017

Brzezinski's remarks come one day after the Trump administration announced it would scrap an Obama-era rule requiring businesses to track how much they pay workers of varying genders, races and ethnicities.

In a statement to The Guardian, Ivanka Trump appeared to support the move, despite her past advocacy for ending the wage gap.

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“Ultimately, while I believe the intention was good and agree that pay transparency is important, the proposed policy would not yield the intended results,” she said in a statement. “We look forward to continuing to work with ... Congress and all relevant stakeholders on robust policies aimed at eliminating the gender wage gap."

Critics of the rule have said that it won't do anything to relieve the gap, and would instead put an undue burden on businesses.

“It’s enormously burdensome,” Neomi Rao, administrator of the Office of Information and Regulatory Affairs, said Tuesday. “We don’t believe it would actually help us gather information about wage and employment discrimination.”

Brzezinski has been deeply involved in other spats with Trump family members in recent months. In July, first lady Melania Trump ripped Brzezinski for implying in an interview that Melania Trump was only sticking around the White House for the sake of her son, Barron Trump.

“It is sad when people try to further their own agenda by commenting on me and my family, especially when they don't know me," Melania Trump wrote at the time.

And in June, Brzezinski was the subject of a particularly nasty Twitter attack from President Trump himself, in which he said "low I.Q. Crazy Mika" was "bleeding badly from a face-lift" during a New Year's visit to his Mar-a-Lago resort in Florida.