BOSTON (AP) — Fewer than 40 votes separate two Republicans seeking their party’s nomination in the state’s 9th Congressional District, according to unofficial returns, raising the possibility of a recount.

Adam Chaprales, of Barnstable, and Christopher Sheldon, of Plymouth, are vying for the November contest against freshman U.S. Rep. William Keating, who won Thursday’s Democratic primary in the reconfigured district.

With all precincts reporting, unofficial returns showed Chaprales leading Sheldon by 39 votes out of nearly 22,000 cast in the Republican primary, a difference of less than two-tenths of a percentage point.

While there is no provision in state law for an automatic recount, a candidate may petition for a district-wide recount if the margin falls below one-half of one percent of the total votes cast.

Chaprales told The Associated Press on Friday that he was still awaiting official returns, which could take several days to be certified. But he said his campaign would proceed as if he were the victor.

‘‘We are marching ahead and we are campaigning as if we are the nominee against Bill Keating,’’ he said.

Asked whether he expected a recount, Chaprales said he was prepared for anything.

In an email to supporters early Friday, Sheldon said that the outcome of the race was still in doubt and that his campaign would be working with city and town clerks in the district to ensure the intent of the voters was honored. But he stopped short of saying whether he intended to seek a recount.

‘‘We are optimistic that the final results in this election will be favorable, and look forward to being part of a Republican victory in November,’’ Sheldon wrote.

Sheldon is a management consultant who serves on the Plymouth County Charter Commission.

Chaprales was elected to the Sandwich Board of Selectmen at age 21, making him the youngest member of the board in town history. He served one term and currently works for the New York Life Insurance Co. on Cape Cod.

The redrawn 9th District includes Cape Cod and the Islands, and much of the South Shore. Keating defeated Bristol District Attorney Sam Sutter in the Democratic primary.

State law allows candidates to petition for a recount in any individual city or town, but a district-wide recount can be requested only when the vote margin is 0.5 percent or lower.