AUGUSTA — The Maine Secretary of State’s Office on Tuesday began recounting more than 20,000 ballots cast during this month’s Republican primary race for Maine’s 1st Congressional District.

Candidate Ande Smith requested the recount after unofficial results showed him trailing Mark Holbrook by 55 votes in the June 14 primary. The winner will challenge incumbent Democratic U.S. Rep. Chellie Pingree in November.

The process began shortly after 9 a.m. in a secure room at the Maine Department of Public Safety, where tables were stacked with locked, metal boxes containing ballots. By 5 p.m., Smith had picked up a modest number of votes – estimated to be in the single digits by both campaigns – after recount teams had hand-checked the ballots from Cumberland County and some of York County.

Cumberland County alone accounts for nearly half of all the ballots that were cast in the Republican contest.

The recount will resume Wednesday morning and is likely to continue into a third day.

Smith, of North Yarmouth, said the process has gone smoothly and his campaign had seen “positive movement.”

“We are moving in the right direction,” said Smith, who estimated he picked up nine votes.

Holbrook, of Brunswick, remained optimistic.

“We’ve talked to people who have been doing this for decades and they don’t expect anything to change the outcome,” Holbrook said Tuesday morning.

Eight recount teams – composed of one representative from each campaign, plus a “recount assistant” – sorted the ballots from each precinct by political party to isolate the Republican sheets before hand-counting the results for the 1st District primary. Each party would then sign off on the results or, in the case of a dispute, set aside those ballots for potential additional scrutiny.

Secretary of State Matt Dunlap reiterated again Tuesday that 55 votes is a substantial margin to overcome in an election in which more than 90 percent of the ballots were counted by machine.

The two men ran a lively campaign for the nomination in a district that has sent a Democrat to Washington, D.C., for all but two years since 1987.

Holbrook is a professional counselor who works with veterans, law enforcement personnel and families in his private practice. A former police officer for more than a decade, Holbrook also has worked as a lobsterman, a commercial diver and an instructor. During the campaign, Holbrook described himself as “the only conservative choice in the race.”

Smith is a former nuclear engineer officer aboard Navy submarines and current captain in the Navy Reserve. An attorney who runs his own consulting firm focused on cybersecurity and technology, Smith argued that his 30-year Navy career as well as his experience in the private sector provided him with the “tools, knowledge and temperament” to lead in Congress. He currently serves on the Maine State Board of Education.

While Smith won many of the larger towns in southern Maine, particularly in the Portland area, Holbrook captured more votes in many midcoast towns and in more rural areas of the district.