The Conservative Party has flagged and removed 1,351 memberships bought through two IP addresses, after leadership candidate Kevin O’Leary accused an unidentified rival campaign of signing up fake members.

The party said the memberships were bought anonymously through the party’s main website and not tied to any specific campaign.

“The memberships purchased in contradiction to the published rules have been removed from our membership list, and are no longer eligible to vote,” the party said in a statement.

Party memberships cost $15, can only be purchased using a credit card or by cheque, and must be bought by an individual “out of their own personal funds.”

O'Leary's campaign had alleged many of the bad memberships were bought using prepaid credit cards. The party said it examined each of the 1,233 memberships bought over the last six months using prepaid credit cards and found roughly half of them came from the two IP addresses.

“We are pleased with the Party for taking our concerns seriously and applaud them for their speed in addressing this issue,” O’Leary said in a statement late Friday. “We are concerned that there will be many more fake memberships submitted at the end of the month when the membership list is finalized.”

He added that there are “clearly forces at work who are trying to influence the outcome. We owe it to the membership to ensure the integrity of the system. The practice of using untraceable, prepaid credit cards must be banned by the Party going forward, and we will remain vigilant in exposing any and all cases where fake memberships have been purchased by sketchy groups trying to buy the Leadership.”

O’Leary did not name any specific campaign when he first raised his allegations. But Maxime Bernier fired back, calling him a “loser” who had to sling mud rather than win on his policies.

"He knows my campaign has raised more money, signed up more members, has more supporters and more volunteers. He's a bad candidate. Instead of trying to win people over by putting out a platform, he's throwing mud to try to save his campaign," Bernier said.

Brad Trost, meanwhile, called O’Leary’s allegations a “publicity stunt,” while Kellie Leitch told O’Leary to “put up or shut up.”

Lisa Raitt, however, joined O’Leary’s call for an investigation.

When I entered this Leadership Race I pledged to put integrity before politics even if it's politically the more difficult thing to do. 1/3 — Kevin O'Leary (@kevinolearytv) March 17, 2017

It's my duty as a Leadership candidate to shed light on the fact that backroom organizers may be vote-rigging in this election. 2/3 pic.twitter.com/DwvXGp9538 — Kevin O'Leary (@kevinolearytv) March 17, 2017

My team has raised this issue directly with Conservative Party officials and I've been told the Party has launched an investigation. 3/3 pic.twitter.com/7Lmugyr04i — Kevin O'Leary (@kevinolearytv) March 17, 2017

Yesterday I informed the Party about the very concerning vote rigging scheme my Campaign has uncovered. https://t.co/TyxkMnS7HD — Kevin O'Leary (@kevinolearytv) March 17, 2017

This is the kind of unscrupulous activity that turns people off politics. This type of deceit is extremely damaging to the Party. — Kevin O'Leary (@kevinolearytv) March 17, 2017

I applaud the Conservative Party for launching an investigation, but that is not enough. — Kevin O'Leary (@kevinolearytv) March 17, 2017

To cast aspersions on the other candidates in this race without a shred of evidence says everything we need to know about @kevinolearytv — Kellie Leitch (@KellieLeitch) March 17, 2017

.@kevinolearytv is the only candidate in the race who's been fined by the party. So it's really something that now he's pointing fingers 1/2 — Kellie Leitch (@KellieLeitch) March 17, 2017