As Virginia elections officials prepared for a recount after state Sen. Mark R. Herring’s narrow victory in the attorney general’s race, Del. Joe T. May announced Monday that he would seek the Republican nomination in the potential race for Herring’s 33rd District seat.

But now, after more than two decades as a Republican representing the 33rd District in the House of Delegates, May has severed his ties to the GOP and is campaigning as an independent.

May had initially anticipated that the nomination would come through a process known as a “firehouse primary.” He favored that method of nomination, according to campaign spokesman Jon Conradi, because it would allow voters to cast ballots at multiple polling locations across the district in a set time frame.

But just hours after May issued his announcement Monday afternoon, the 33rd Senate Republican Legislative District Committee instead called for a Dec. 16 “mass meeting” in Sterling to determine the nominee.

May responded Tuesday by breaking from the party and criticizing the GOP committee for a decision that he said would exclude “all but a handful of voters” from the process.

“Just hours after I had announced my intention to run in a firehouse primary, that good faith was rewarded by an attempt to deprive the voters of the 33rd district the opportunity to vote in a fair and open process,” May said in a statement. “I have been contacted by a very large number of people who have expressed their outrage over what has happened. And those people are Republicans. Virginia and the Republican Party deserve better.”

May said it was “unacceptable” that a handful of Republican committee members had met to determine the date, location and requirements of the mass meeting — including a provision stating that no one who has voted in a Democratic primary since March 1, 2004, be allowed to cast a vote.

Last week, Herring was certified the winner of the attorney general’s race by 165 votes over state Sen. Mark D. Obenshain (R-Harrisonburg). But the vacancy of Herring’s seat will only become certain if that outcome is confirmed by a recount, which is slated for the week of Dec. 16.

May’s campaign staff noted that Virginians in other areas of the district, which includes parts of Loudoun and Fairfax counties, would find it difficult to participate in a meeting held on a weeknight in Sterling.

May, whose reelection bid was upended in June by conservative newcomer Dave LaRock in the GOP primary, said that he would follow in the footsteps of the late U.S. Sen. Harry F. Byrd Jr. by running as an independent for the state Senate.

“I have been a Republican and a conservative all my life. But today, I join Sen. Byrd as an independent and I am a candidate for the state senate of Virginia,” May said in his statement. “I ask for the support of every Virginian in the 33rd district — Republican, Independent and Democrat alike. We must ensure every voter has the opportunity to participate and to be heard. We must reject Washington style politics in our great Commonwealth.”

On Thursday, Mark Sell, chairman of the 33rd Senate Republican Legislative District Committee, said in an e-mailed statement: “I am deeply disappointed with Joe May’s decision to run as an independent despite our efforts to ensure a fair and open process allowing full participation of all Republicans. We expect our nominee to be victorious in the upcoming special election with the full support of the Committee’s membership.”

At the Dec. 16 meeting, Republicans will choose between two candidates vying for the party’s nomination: conservative pundit Ron Meyer, 24, who had previously announced plans to challenge Rep. Gerald E. Connolly (D) next year; and 10th Congressional District Republican Committee Chairman John Whitbeck, a lawyer who drew criticism in September after he told an anti-Semitic joke at a rally for GOP gubernatorial candidate Ken Cuccinelli II. Whitbeck later apologized for the remark.

The GOP nominee would face May and Jennifer Wexton, a Leesburg lawyer and former county prosecutor who won a Nov. 23 Democratic firehouse primary, for Herring’s seat.

A date for a special election has not been announced.