As provisional and vote-by-mail ballots are counted, state Sen. Tom McClintock's (R-Thousand Oaks) lead in the 4th Congressional District widened slightly Thursday morning, up to about 640 votes ahead of Democrat Charlie Brown.

Still unclear was how many ballots remain to be counted; Brown said in a statement Wednesday that he believed as many at 40,000 ballots were still to be processed. Neither campaign has formally conceded or claimed victory as of yet.

An official in the California Secretary of State's communications office said state officials hope to receive a report later today from counties in the 4th and elsewhere on how many ballots they still have to count.

The official noted that provisional ballots take longer to count because voting officials must first verify that the person who cast the ballot is eligible and registered to vote and hasn't already done so in that election.

Once that's done, the ballot is formally processed.

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• Brown says 40,000 votes still to be counted in CD-04 race
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