U.S. Rep. Michael Grimm, R-N.Y., may be embroiled in controversy after witnesses at a Brooklyn bar claimed he acted inappropriately – including going into a restroom with a woman for 15 minutes and slapping the rear end of his female companion.

The congressman has yet to respond to the allegations.

The unmarried congressman, who represents Staten Island and nearby parts of Brooklyn, was in a Bay Ridge bar Sept. 27 – the Friday before the government shutdown – when he allegedly engaged in the shenanigans, Brooklyn Magazine reported Tuesday.

One witness told the publication that Grimm and a woman spent such “a long f----- time,” or about 15 minutes, in the bar’s bathroom “that people at the bar were talking about it.”

“I was surprised someone so sleazy could be a congressman,” one of the witnesses told Brooklyn Magazine.

Grimm, 43, is a Marine combat veteran of the 1991 Persian Gulf War and former FBI agent who was first elected to Congress in 2010. He was briefly married in 2004, but the union was annulled. He is the only Republican in the New York City delegation.