Martin Prud'homme, the head of the Sûreté du Québec, has been suspended after an "allegation related to criminal offences."

Public Security Minister Geneviève Guilbault said she was informed Tuesday of the situation, but refused to answer questions about the nature of the allegation, including whether it is related to Prud'homme's duties at the provincial police force.

"We wanted to act quickly, we wanted the public to be reassured, and we wanted, most of all, not to interfere with the ongoing investigation," she told reporters at a news conference Wednesday.

Quebec's bureau of independent investigations, known by its French acronym, BEI, is leading the investigation.

The BEI is looking into allegations that Prud'homme was involved in information leaks from an investigation conducted by UPAC, the province's anti-corruption unit, Radio-Canada is reporting.

That investigation is related to Quebec Liberal Party financing under Jean Charest and former PLQ treasurer Marc Bibeau.

Guy Ryan, a former SQ officer who has been following the situation, called the allegation a "bomb" within the SQ, the province's largest police force, with 8,000 officers.

He said Prud'homme's suspension puts the credibility of the force in question.

Guilbeault stressed that Prud'homme, who was appointed to head the SQ by the Liberal government in 2014, has not been arrested or charged, and the suspension is described as an administrative measure.

Line Bérubé, the civil servant who heads the branch of government that manages employees in senior positions, made the decision to suspend Prud'homme. Mario Bouchard, assistant director general of the SQ, will replace him in the interim.

Tapped to help reform Montreal police

Prud'homme recently returned to his position at the provincial police service after a year-long assignment as interim chief of Montreal police (SPVM).

He was named to the position by former public security minister Martin Coiteux following allegations of misconduct involving the SPVM's internal affairs division.

At the time, Coiteux said they needed someone "solid" to lead Montreal police.

Christine St-Pierre, a Liberal MNA and the Opposition's public security critic, called the situation "worrisome."

"It was the duty of the government to suspend Mr. Prud'homme. The confidence of the population is very, very important. We need to have the light of the situation very rapidly," she said.