Mark Salter, a longtime aide to the late Sen. John McCain John Sidney McCainCindy McCain endorses Biden: He's only candidate 'who stands up for our values' Biden says Cindy McCain will endorse him Biden's six best bets in 2016 Trump states MORE (R-Ariz.), criticized the National Republican Senatorial Committee (NRSC) on Twitter Saturday for trying to undermine Rep. Kyrsten Sinema's (D) lead in the Arizona Senate election.

"Stop doing this, NRSC," he wrote.

"McSally is losing fair and square, and she’s underperforming in more than Maricopa. The race is almost certainly lost and nothing will change that. All this does is poison our politics more. Despicable."

Stop doing this, NRSC. McSally is losing fair and square, and she’s underperforming in more than Maricopa. The race is almost certainly lost and nothing will change that. All this does is poison our politics more. Despicable. https://t.co/b5ma1o0ikD — Mark Salter (@MarkSalter55) November 10, 2018

Salter was referring to attacks from a spokesman at the NRSC, Senate Republicans' campaign arm, aimed at vote-counting efforts in Arizona where Rep. Martha McSally Martha Elizabeth McSallyTumultuous court battle upends fight for Senate Grassley, Ernst pledge to 'evaluate' Trump's Supreme Court nominee The Hill's Campaign Report: Biden goes on offense MORE (R) trailed her opponent in the state's yet-to-be-called Senate race.

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The Arizona Senate race has remained in the national spotlight as one of two Senate seats yet to be decided following Tuesday's midterm elections, the other being a contest between Florida Gov. Rick Scott (R) and Sen. Bill Nelson Clarence (Bill) William NelsonDemocrats sound alarm on possible election chaos Trump, facing trouble in Florida, goes all in NASA names DC headquarters after agency's first Black female engineer Mary W. Jackson MORE (D-Fla.).

Democrats hoped to retake the Senate and House in Tuesday's elections, and while the party saw dozens of seat gains in the House, a Senate majority remained firmly in the hands of Republicans.

The Hill has reached out to the NRSC for comment.