NEW YORK — MSNBC says journalist Mark Halperin has been suspended from his role as network contributor following charges from five women who claimed he sexually harassed them while he was an ABC News executive.

Mark Halperin is accused by five women of sexually harassing them when he worked at ABC News. Associated Press/Sue Ogrocki

The network said Thursday it found Halperin’s conduct as described in a CNN story “very troubling” and that the veteran political reporter will be off the air until questions about his past are fully understood.

Later Thursday, Penguin Press canceled a planned book by Halperin and John Heilemann about the 2016 election and HBO called off a miniseries that would have been based on the book. Halperin and Heilemann had collaborated on two previous books, including “Game Change,” a best-seller about the 2008 race that almost single-handedly revived the campaign book genre and was the basis for an award-winning HBO adaptation.

The planned book had no title or publication date, but had been expected to be released in early 2018.

Halperin has apologized for what he termed inappropriate behavior, and ABC said Thursday that no complaints were filed against him during his tenure, which ended more than a decade ago.

The women, who asked to remain anonymous, said they didn’t report Halperin’s conduct because they feared retribution or were embarrassed.

But Emily Miller, a former ABC employee who is now a reporter at One America News Network, retweeted the Halperin story on Thursday with the hashtag “#MeToo.” She gave no details of her alleged incident, but tweeted that she did not report Halperin to ABC “because I thought I was the only one, and I blamed myself, and I was embarrassed and I was scared of him.”

CNN international correspondent Clarissa Ward, who also used to work at ABC, tweeted that Halperin’s behavior was “an open secret” at the network.

“Let’s be very clear – the one responsible for any sexual misconduct that may have taken place is the man who instigated it,” Ward tweeted, “NOT the women who were victims of it, nor their friends and colleagues who tried to support them through it.”

Halperin told CNN Wednesday night that he’s “deeply sorry” and is taking a “step back” from day-to-day work to deal with the situation. CNN reported allegations that Halperin propositioned, fondled and pushed himself against five women in the early 2000s when he was ABC’s political director.