The gap between Congresswoman Mary Bono Mack of Palm Springs and her Democratic challenger increased slightly Thursday night as newly counted ballot numbers were released by Riverside County election officials.
Bono Mack had refused to concede Tuesday after initial results showed her losing to Dr. Raul Ruiz, with her campaign pointing to more than 180,000 uncounted ballots in the county.
With more mail-in ballots counted by Thursday evening, new numbers from the Riverside County Registrar of Voters showed that Ruiz's lead opened up just slightly. He had gained 122 more votes than Bono Mack had, for a new gap between the candidates of 4,679 votes.
Ruiz, an emergency room doctor who got backing from national Democratic figures including Bill Clinton, had 51.41 percent of the vote to Bono Mack's 48.59 percent on Thursday.
Bono Mack, a 51-year-old Republican, won her seat 14 years ago in a special election to replace her husband, Sonny Bono, who had died in a skiing accident.
Her campaign had said Wednesday that it was "premature" to consider results final, noting some 180,000 ballots still to be counted throughout Riverside County.
"Congresswoman Mary Bono Mack and her campaign will be awaiting the impact of this large number of remaining ballots before making any further statements on the 36th Congressional District race," said Marc Troast, Bono Mack's campaign political director, on Wednesday.
The Registrar of Voters reported Thursday that it still had 86,000 mail-in ballots, 60,000 provisional ballots and 18,000 damaged ballots still to count.
It was unclear how many of those uncounted ballots were in the 36th Congressional District, which stretches from Hemet east across the Palm Springs and Coachella Valley area to the Arizona border.
A new update was expected at 6 p.m. Friday.
NBC News has already projected Ruiz the winner of the race.
Ruiz told the Associated Press he Ruiz said he had been thanking his constituents for their support and was looking forward to going to Washington next week for freshman orientation meetings.
City News Service contributed to this article.