MONTREAL - Thursday's splashy celebration of Montreal's 370th anniversary was quickly overshadowed by news of the high-profile arrests of three former members of Mayor Gerald Tremblay's inner circle.

Opposition councillors took to the attack, saying that the three term mayor must have known something was amiss.

"The mayor is the mayor, he's responsible for everything, bad things and good thing too," said Anie Samson, a councillor for the opposition Vision Montreal and borough mayor of Villeray–Saint-Michel–Parc-Extension.

With the mayor's former right-hand man, former chief-of-staff and former chief fundraiser were held in custody by the Surete du Quebec's permanent anti-corruption squad, UPAC, members of the opposition hinted that it was time for Tremblay to go.

"The noose is tightening around Mayor Tremblay. His inner circle has been arrested and this is an indictment of his entire administration," said Project Montreal councillor Alex Norris.

As for the mayor, he says he has already been questioned by the police, however he won't say how many times or for how long.

"It's a very difficult moment," said a visibly upset Tremblay. "I was asked to answer certain questions, which I did, and as a result of that the police is doing what it has to do."

Tremblay pointed out that the alleged events date back several years, since then, he says that his administration has put in place new measures to fight corruption and avoid conflict of interest. As far as whether or not any money ever went back to his party, he doesn't know.

"We've asked the director general of elections to do whatever audit he had to do, so it's been 11 audits and no accusation has been put to Union Montreal," said Tremblay, referring to his ruling party.

Back in the mayor's first term, Robert Libman sat on the executive committee that was chaired by Frank Zampino, arrested on Thursday. He said he was surprised by the arrests.

"I sat through hundreds of executive committee meetings with Frank Zampino and I never got the impression that he was trying to unduly influence the executive committee," said Libman.

Still the arrests come as a major blow to the Tremblay team, with some wondering how deep this can run.

"Now that we see the arrests coming down we hope it will keep coming and we will get to the bottom of this," said Etienne Brunet, a city councillor for Vision Montreal.

For now, those arrested are getting ready to face the justice system. The mayor admits once again that the public's confidence in elected officials has been hurt. First elected in 2001, Tremblay has hinted that he might be interested in pursuing a fourth term in the 2013 elections.