A federal judge has ordered U.S. Postal Service inspectors to sweep postal facilities on Tuesday in several locations — including in six battleground states — to ensure that any mail-in ballots left behind are immediately sent out for delivery.

The last-minute order on Tuesday by Judge Emmet G. Sullivan in Washington, D.C., directs the law enforcement arm of the Postal Service to inspect facilities in central Pennsylvania, Philadelphia, Detroit, Atlanta, Houston, south Florida, Arizona and a few other locations between 12:30 p.m. and 3 p.m. Eastern time.

The order is part of one of several lawsuits against the Postal Service over cost-cutting measures that slowed mail delivery this year and raised concerns that mail-in ballots would not be delivered on time.

Recent data has shown that on-time mail delivery in some parts of the country has dropped to levels lower than in July, when millions of Americans went days, even weeks, without mail.

The order focuses on postal districts that have struggled to deliver ballots on time in recent days. It also centers on states that will not count ballots received after election day.

“No one should be disenfranchised for something that is out of their control. It’s important that the Postal Service do everything in its power to make sure that that doesn’t happen,” said Shankar Duraiswamy, an attorney for Vote Forward, a voting rights organization that filed the lawsuit prompting Sullivan’s order.

A Postal Service spokesman did not immediately respond to a request for comment.