(CNN) - Sen. John McCain's presidential campaign sent back $3 million in donations, an aide confirms to CNN.
The return of the donations seems to suggest that the presumptive Republican presidential nominee might be planning to accept public financing for the general election.
Presidential candidates can receive a maximum of $4,600 from any single donor: $2,300 for their primary run, and $2,300 for the fall campaign. But if they accept government funds for the general election campaign, they are only allowed to keep the first $2,300.
McCain will still be able to use much the money, if donors who have had their checks returned re-direct them to his “general compliance fund” instead – a move he has requested in a letter to supporters.
(General compliance funds are used for legal expenses that arise from Federal Election Commission requirements, including related payroll and fundraising costs.)
Neither of the Arizona senator’s potential fall opponents will likely be bound by the fundraising limits of the federal public financing system.
Sen. Barack Obama, who had earlier pledged to accept public money if the GOP nominee did as well, has been more equivocal on his plans since becoming the Democratic frontrunner. Sen. Hillary Clinton has said that she will not participate in the program.