March 14 (UPI) -- Democrat Conor Lamb declared victory Wednesday afternoon in the special election for Pennsylvania's District 18, but Republican Rick Saccone said he intends to challenge the close results.
The New York Times called the race for Lamb after thousands of absentee ballots were counted. The ballots gave the Democrat a 627-vote advantage with about 500 provisional, military and other absentee ballots left to count.
"It took a little longer than we thought, but we did it. You did it," Lamb told supporters in Canonsburg, Pa.
But Republican officials are alleging voting irregularities in the congressional race.
Even with a margin that close, state law does not require an automatic recount in congressional races. Parties can request it after all the votes are tallied.
A statement by the National Republican Congressional Committee said it was confident Saccone will take the lead in the end.
"This race is too close to call and we're ready to ensure that every legal vote is counted. Once they are, we're confident Rick Saccone will be the newest Republican member of Congress," said NRCC communications director Matt Gorman. "The NRCC is proud of our efforts in this race to promote Rick's message, motivate Republican voters and hold Conor Lamb accountable."
Saccone said late Tuesday that if the counting of provisional and military absentee ballots failed to bring victory his campaign could seek a recount.
"We are still fighting the fight. It's not over yet," he said.
The race -- in which a Lamb victory would flip the Republican seat -- is considered a bellwether for the November midterms. President Donald Trump handily won the district in 2016 over Democratic nominee Hillary Clinton.
Rep. Tim Murphy vacated the seat in October after a scandal involving a staffer.
The winner of the race will serve out the remaining 10 months of Murphy's term, but will have to win a new district to continue in November -- after an anti-gerrymandering decision last month by the Pennsylvania Supreme Court that realigned congressional boundaries.
Jakob Lazzaro of Medill News Service contribute to this report.