CRANBERRY TWP — Republican Sean Parnell on Thursday contested U.S. Rep. Conor Lamb's claim to victory with a less than 1 percentage point margin in the 17th Congressional District.

Declining to concede in the slim race, Parnell's campaign issued a statement calling for “every vote” to be “counted and verified as legal,” while also raising issue — although declining to name specific examples — of “widely reported irregularities.”

“Last night, despite previously calling for every vote to be counted, Conor Lamb claimed victory practically the minute he took a slim lead in this race,” Parnell's campaign manager, Andrew Brey, said in the statement. “Unless Lamb has a sixth sense that helps him precisely determine vote totals from outstanding precincts in this razor's edge race, he should exercise the restraint that he was calling for while significantly behind.”

Lamb, who represents parts of Cranberry Township, anointed himself winner in the race shortly after 10 p.m. Wednesday, but vote tallies from The Associated Press showed Lamb trailing Parnell until 8:55 a.m. Thursday, when their tallies showed Lamb with a slight lead with 96% of precincts reporting.

As of 3 p.m. Thursday, Lamb held the lead in the district by fewer than 5,000 votes, or about 1.04 percentage points across the three-county 17th District. With nearly all mail-in ballots counted in Butler and Beaver counties, the remaining 35,000 mail-in ballots yet to be counted in Allegheny County will likely determine the fate of this closely watched race.

Lamb, who could not be reached for comment Thursday, rallied in Butler County with the arrival of mail-in results. Although Parnell led by about 3,500 Election Day votes, more than 3,100 mail-in ballots have gone to the incumbent, while 1,500 went to Parnell, shrinking Parnell's edge to 14.5 percentage points in the county.

Beaver County similarly went for Parnell by a 16-point margin, leaving Lamb's lead to come from Allegheny County which, as of 3 p.m. Thursday, had voted for him 53.4% to 46.6%.

The AP, which has projected victors in other races in Butler County and Western Pennsylvania, has not called the race for either Lamb or Parnell.

Lamb, a Marine Corps veteran and former federal prosecutor, was first elected in a 2018 special election following the resignation of former U.S. Rep. Tim Murphy, R-18th, amid controversy. He won reelection in November 2018 against Republican Keith Rothfus by a 13-point margin.