ATLANTA (AP) — Thousands of voters in Georgia's third-largest county who received their mail-in ballots late will not get an extension to return them, the state's highest court ruled Monday.

Cobb County, north of Atlanta, did not send mail-in ballots to around 3,400 voters who had requested them by the end of last week. Georgia law requires mail-in ballots to be received by the close of voting on Election Day. But a lower court judge ruled last week that the ballots in question could be counted if they were received by Friday, three days after Election Day, as long as they were postmarked by Tuesday.

The Georgia Supreme Court's ruling means affected Cobb County residents must vote in person on Election Day, Tuesday, or drop off their mail-in ballots at the county election office by 7 p.m. that day.

The Supreme Court ruling directs county election officials to notify affected voters via email, text message and in a public message on the county elections board website. And it directs officials to separately store and seal any ballots received after the Election Day deadline but before 5 p.m. on Friday.

Board of Elections Chairwoman Tori Silas said the board will comply with the Supreme Court's order, but it is still uncertain whether ballots received after Election Day will be counted. The order addressed only a request for a stay, so election officials will have to wait for the court's final decision to see whether votes received after Tuesday will be counted, she said in a statement.

To deliver ballots on time, election officials in Cobb County used U.S. Postal Service priority mail and UPS overnight delivery and mailed ballots using prepaid express return envelopes. The elections board said more than 1,000 of the late mail-in ballots were sent to people outside of Georgia.

Last week, Silas blamed the delay in mailing ballots on faulty equipment and a late surge in absentee ballot requests in the week before the Oct. 25 deadline.

The original decision to extend the deadline stemmed from a lawsuit filed by the American Civil Liberties Union and the Southern Poverty Law Center on behalf of three Cobb County voters who said they had not received absentee ballots in the mail by Friday.