WASHINGTON (CNN) -- Sen. John McCain will begin raising private funds for the presidential general election but has also agreed to return that money and accept public funding if he wins the GOP nomination and his Democratic counterpart agrees to do the same.

The McCain campaign's decision came after the Federal Election Commission ruled Thursday to allow presidential candidates to tentatively raise private money for the general election while reserving the option of returning that money and accepting public funds at a later date.

"John McCain welcomes the FEC's ruling that presidential campaigns can accept general election funds with the option to return the funds and participate in public financing once the general election phase of the campaign has begun," said McCain campaign manager Terry Nelson in a statement to CNN. "The McCain campaign will now begin the process of accepting these general election funds, following the new FEC guidelines. Should John McCain win the Republican nomination, we will agree to accept public financing in the general election, if the Democratic nominee agrees to do the same."

The FEC issued its ruling after an inquiry from Democratic presidential candidate Barack Obama, who was the first to suggest a general election public funding accord between the eventual major party nominees.

Former New York City Mayor Rudy Giuliani will also begin to raise private general election funds, a campaign aide told CNN earlier Thursday, but he has not decided whether he will eventually return that money in favor of public funds.

Democrats Hillary Clinton and John Edwards have both said they will fund both their primary and possible general election campaigns solely from private funds, forgoing up to $105 million in public money. Neither candidate responded to inquiries as to whether they would return any general election contributions if the Republican nominee agrees to do so as well.

Candidates who accept public funding are eligible for up to $21 million during the primaries and approximately $84 million in the general. No major party nominee has ever refused general election public financing since the program began in 1976.