Republicans are eying recount hopes, as about 600 votes separate Democrat Conor Lamb and Republican Rick Saccone in Pennsylvania's special election. Lamb has declared victory, but there are still some ballots outstanding.

Absentee votes counted from Greene County on Wednesday put the difference between the two candidates at 627 votes. Saccone isn't yielding the race, even as pundits are saying it would be nearly impossible for him to win based on the number of absentee and provisional ballots remaining.

A source familiar with the situation tells CBS News' Rebecca Kaplan that all four counties have complied with a request to impound their voting machines and ballots so they can be reviewed. The vote tallies must be certified before the Saccone campaign can call for a recount, but the source called a recount "probable" at this point.

The Saccone campaign believes it has at least three documented cases of voters being turned away or having issues voting, which could become a part of a lawsuit, CBS News' Nicole Sganga reports. Saccone will try a run in the state's 14th congressional district if he isn't victorious in the 18th district, political consultant Bob Branstetter told CBS News early Wednesday.

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Saccone hasn't publicly spoken since late Tuesday night, when he thanked supporters and assured them he wasn't giving up anytime soon.

Pennsylvania law has no provision for automatic recounts for congressional races.