Belgian Justice Minister Vincent Van Quickenborn told parliament on Thursday that he did not know that three of his friends had urinated on a police car during a party at his house, and denied that he was joking about it, Reuters reported.

Belgium has been rocked by what the media has dubbed “peegate” after the media released security camera footage showing three of Vincent Van Quickenborn’s guests urinating on a police van guarding the minister’s residence.

Opposition politicians and police unions have also expressed outrage at footage of Van Quickenbourn mimicking the actions of his guests and joking about it at the end of his 50th birthday.

At a parliamentary hearing, Van Quickenborn apologized and said he was unaware of the incident that night.

“I’m ashamed that the people I invited to my home peed on a police van, not once, but three times. It’s disgusting, especially considering what the van is there for,” he said.

Van Quickenborn is under 24-hour security after being the victim of a botched kidnapping attempt last year.

He disputed CCTV footage which showed him laughing about the incident later that night as he sat outside with a guest.

Van Quickenborn said he did not have access to the police videos, but he showed footage from his home’s surveillance cameras in parliament.

“Some people say that I’m pretending to pee in these photos. The person I was accompanying with thinks I’m…copying an air guitar solo…I admit I do sometimes…It’s possible, I honestly don’t know,” he said.

He added that the prosecutor’s office has opened an investigation.

Opposition politicians criticized Van Quickenborn.

“You have given a completely new dimension to the concept of a Belgian joke,” said Ingvild Ingels, a member of the opposition N-VA party.