MONTREAL -- Police are investigating online threats against Quebec City's mayor.

On Tuesday, Mayor Regis Labeaume said he had filed a police complaint over the threats. Quebec City police confirmed they had opened an investigation.

The announcement came a day after the City of Quebec announced it would no longer advertise on CHOI Radio X. Labeaume said he had received nearly 4,000 messages since that announcement, with at least one of those messages being particularly aggressive.

The station is accused of promoting “opposition to sanitary measures” and constituting a “danger to public health” over programming where anti-COVID-19 measures were criticized. In recent weeks, several of the station's hosts encouraged listeners to defy pandemic health measures such as wearing masks and interviewed guests who are known conspiracy theorists.

Several other advertisers, including Hydro Quebec and Uniprix, also pulled their advertisements.

The station's owner, RNC Media, said on Monday they would continue to inform listeners while maintaining a critical position.

The company insisted it would not accept “any biased and spurious association with the conspiracy movement.”