Lawmakers on Friday urged the Postal Service urged the U.S. Postal Service to halt work on new mail-in voting rules, saying they threaten the integrity of the November congressional elections.

“The Postal Service’s continued illegal attempts to turn itself into an election administration agency at the direction of President Trump risks disenfranchising eligible American voters and threatens the integrity of upcoming elections,” wrote Senator Gary Peters and the other six Democrats on the Senate Homeland Security and Government Affairs Committee that oversees the USPS in a letter seen by Reuters.

Late Thursday, President Donald Trump’s administration asked the Supreme Court to let it enforce the new USPS rule tightening the use of mail-in ballots.

(Reporting by David ShepardsonEditing by Nick Zieminski)