“It’s clear that concerns about General Flynn’s ties to Russia were well warranted,” Rep. Eliot Engel (D-NY), the ranking Democrat on the House Foreign Affairs Committee, said Friday in a statement.

Democrats have since the campaign been raising questions about Flynn, who in 2015 accepted a fee to speak at the 10th anniversary of RT, the English-language broadcaster widely seen as a Russian government propaganda outlet.

Flynn also has been a booster of closer ties with Russia, whose government, under President Vladimir Putin, has been reviled as repressive and corrupt by Democrats and Republicans.

Obama in December slapped sanctions on Russia because of its alleged spying in the United States and because the U.S. intelligence community expressed a high degree of certainty that Russia attempted to meddle in the U.S. elections.

It was revealed shortly thereafter that Flynn had spoken with Russia’s ambassador to the United States just after Obama imposed sanctions, but Flynn and Sergey Kislyak, the ambassador, said the calls were routine and did not address the sanctions.

On Thursday, the Washington Post quoted nine intelligence officials who were familiar with the calls as saying that sanctions were indeed discussed. Inthe article, Flynn backed away from his earlier denial, leading some Democrats – chief among them Engel – to call for his removal.

“It’s unacceptable that during the transition, General Flynn discussed lifting sanctions with Russia’s ambassador,” Engel said.

According to the reports, Flynn suggested to Kislyak that Trump would roll back the sanctions, making the case to him that Russia should not retaliate against Obama.

“This action would be deeply troubling under any circumstances, but considering Russia’s effort to tip the election toward President Trump, the General’s actions are disqualifying,” Engel said. “And if General Flynn negotiated with Russia to change American policy, he may be in violation of the Logan Act, which bars such conduct. The President must relieve General Flynn immediately.”

The Logan Act is law against unauthorized citizens interfering in U.S. disputes with foreign governments. There has never been a prosecution under the act.

Engel’s district includes parts of the Bronx and Westchester County.