NBC News has suspended contributor Mark Halperin pending an investigation into allegations by several women that he sexually harassed them while he was an exec at ABC News.

“We find the story and the allegations very troubling. Mark Halperin is leaving his role as a contributor until the questions around his past conduct are fully understood,” the network news operation said in a statement, after CNN broke the news of the allegations last night.

Early Thursday morning, MSNBC’s Morning Joe co-host host Mika Brzezinski addressed the absence of Halperin, a show regular:

Now to a story that broke overnight involving someone you see around this table every day. CNN is reporting allegations regarding our friend Mark Halperin during his time at ABC News over a decade ago, unnamed sources detailing unwanted advances and inappropriate behavior. Halperin apologized for the pain his actions caused and said “I will take a step back from my day-to-day work while I properly address the situation.” We are going to be following this story as it develops. I’m sure we are going to be talking about it again when we know more about it.

Five women have come forward to accuse the NBC News analyst and veteran journalist of sexual harassment during his days at ABC News. ABC furnished CNN with a statement in its report:

“Mark left ABC News over a decade ago, and no complaints were filed during his tenure.”

Halperin responded with his own statement to the cable news network’s piece: “During this period, I did pursue relationships with women that I worked with, including some junior to me…I now understand from these accounts that my behavior was inappropriate and caused others pain. For that, I am deeply sorry and I apologize. Under the circumstances, I’m going to take a step back from my day-to-day work while I properly deal with this situation.”

Halperin also is co-host of Showtime’s The Circus, chronicling the 2016 campaign cycle and the early days of Donald Trump’s presidency. He also co-wrote with John Heilemann Game Change, about the 2008 presidential election, which was turned into a 2010 HBO movie. He currently has a project in development with HBO.

The harassment accusations from unnamed women include propositioning employees for sex, kissing, and grabbing breasts without consent. Three of the women who spoke to CNN said Halperin pressed an erection against them while he was clothed, without their consent. Halperin denied grabbing a woman’s breasts and pressing his genitals against these three women. CNN reported that none of the women reported to Halperin nor did they claim he promised anything in exchange for sex or suggest retaliation.