PHILADELPHIA, Pennsylvania (BLOOMBERG) - Pennsylvania Republicans sued officials in a suburban county near Philadelphia that is expected to heavily favour Democrats, alleging they illegally allowed mail-in ballots to be counted before Election Day.

The suit targeting Montgomery County officials was filed in federal court in Philadelphia on Tuesday (Nov 3) by a Republican candidate for Congress and chairman of the Republican Party in neighbouring Berks County. Late on Tuesday, a county spokesman said only 49 ballots were involved.

In Pennsylvania, vote tabulation is prohibited until 7am on Election Day.

Republicans also allege Montgomery County officials are allowing some voters with defects in their ballots to correct them. They are asking a federal judge to stop the county from contacting any voter whose ballot is defective and order that any defective or revised ballots be set aside.

According to the suit, the county's Board of Elections had identified at least 1,200 ballots that were defective as at Oct 31.

The county believes that its process is "sound and permissible under the Election Code", Kelly Cofrancisco, a spokesman for Montgomery County, said in a statement. She said a hearing in the matter was scheduled for 9am on Wednesday.

Biden suburbs

Montgomery County and other Philadelphia suburbs are expected to favour Democrat Joe Biden. In 2016, nearly 60 per cent of Montgomery County voters went for Hillary Clinton.

The suit comes after President Donald Trump pledged a fierce legal fight over vote counting that would drag on after polls close.

The battle so far has focused mostly on curtailing Democratic efforts to loosen rules for voting by mail.

Local Democrats have said staff at polling places have always helped voters ensure they are casting ballots correctly and that county officials weren't overstepping while contacting voters, the Philadelphia Inquirer reported.

Some issues with ballots, such as whether a voter forgot to sign the envelope, are evident before they are opened, the Inquirer said.

The Republican lawsuit further claims that Montgomery County officials are restricting their ability to monitor the count by forcing their representatives into a "tiny holding pen" that doesn't allow them to adequately view the proceedings or in an overflow room with televisions.

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