The U.S. Postal Service on Tuesday said it could not meet a federal judge’s order to sweep processing centers for undelivered mail-in ballots, arguing that doing so would disrupt its Election Day operations.

U.S. District Judge Emmet G. Sullivan of Washington, D.C., gave the agency until Tuesday afternoon to search 27 facilities in several battleground areas for outstanding ballots and send out those votes immediately.

In its response, the Postal Service said it had already conducted rounds of morning checks at all its processing hubs.

Further, the agency said it has been performing daily reviews of all 220 facilities handling election mail and planned another sweep hours before polling places closed Tuesday.