Bernie Sanders' presidential campaign is requesting a recanvass in Kentucky's presidential primary, where he trails Hillary Clinton by less than one-half of 1 percent of the vote.

The Sanders campaign said it planned to ask the Kentucky secretary of state to have election officials review electronic voting machines and absentee ballots from the May 17 primary in each of the state's 120 counties.

A spokesman for Secretary of State Alison Lundergan Grimes said Sanders' campaign sent the written request Tuesday. Unofficial vote totals showed Clinton beating Sanders by less than 2,000 votes.

“My office is notifying all county boards of elections that Sen. Sanders has requested a recanvass, and we are reminding them of the laws and procedures to be followed,” said Grimes. “As always, we will assist the county boards of elections in any way we can.”

Clinton holds 1,924-vote lead over Sanders out of 454,573 votes cast. The Associated Press did not called the race, despite Clinton's slight lead, in the event that Sanders might ask to recanvass the vote. Multiple news outlets said it was mathematically impossible for Sanders to win, and Clinton later declared herself the winner.

Both Clinton and Sanders received 27 delegates, but one delegate remains to be allocated in a congressional district that includes Frankfort and Lexington.

A recanvass is not a recount but a review of the voting totals. The purpose of a recanvass is to verify the accuracy of the vote totals reported from the voting machines.

Grimes' office said county boards of elections will convene at 9 a.m. local time on May 26 to recheck and recanvass the voting machines, per Kentucky law. The boards will notify the candidates of the location of the recanvass. Immediately upon completion of the recanvass, the boards will file their recanvass reports with the Secretary of State.

Each candidate and both political parties may have a representative present at the recanvass, and the county board of elections shall authorize media to observe.

In addition to the Democratic presidential primary, the Jefferson County Board of Elections will also recanvass the results in the Republican primary for State Senate, 33rd District, at the request of candidate John Yuen who trails his opponent, Shenita Rickman, in unofficial totals.

Candidates had until 4 p.m. Tuesday to submit a recanvass request in a primary election.

The last statewide recanvass was conducted last year in the Republican Gubernatorial primary at the request of James Comer/Chris McDaniel, candidates for Governor and Lieutenant Governor. The margin was 83 votes and the recanvass did not change the results or outcome of the election.

Meanwhile, Clinton and Sanders are dueling for support ahead of California's presidential primary on Tuesday. The Vermont senator is showing few signs of backing off as he seeks to boost his longshot odds for the Democratic nomination.

The Democratic hopefuls are campaigning in California, where Clinton hopes to make a statement in the June 7 contest that will encourage the party to coalesce around her candidacy. Sanders is aiming for an upset and airing a new ad in the state.