FRANKFORT, Ky. — The federal government has denied Kentucky’s request for more time to update its drivers’ licenses, potentially forcing residents to use passports to board domestic flights by 2018.

The U.S. Department of Homeland Security notified state officials Wednesday that it had turned down Kentucky’s request for an extension to comply with the federal Real ID Act. Congress passed the law in 2005 in response to the Sept. 11 terrorist attacks. Kentucky is one of several states that had been granted more time to comply. But Kentucky’s extension expired Monday, and the federal government did not renew it.

State lawmakers passed legislation earlier this year to bring Kentucky in compliance with the requirements. Republican Gov. Matt Bevin endorsed the legislation, even posting a video to his Facebook page saying Real ID was “nothing to be concerned about.” But a few days before he was to sign the bill, the Republican Party of Kentucky passed a resolution condemning the law. Bevin then changed his mind and vetoed it, saying it was “rushed” and he wanted to see what impact the next president would have on the issue.

Bevin said in a news release Wednesday he would again ask the legislature to pass a law complying with Real ID requirements. The legislature isn’t scheduled to convene again until January.

“We felt like we met all of the criteria (the federal government) set forth for an extension request,” said John Mark Hack, Bevin’s commissioner for the Kentucky Department of Vehicle Regulation. “This being October and two weeks before a national election, strange things happen. I don’t understand their reasoning.”

Kentucky was one of six states whose extension was under review by the federal government.

Because the federal government denied the extension, beginning Jan. 30 Kentuckians won’t be able to use their drivers’ licenses or ID cards to enter military bases or nuclear power plants. Kentucky has no nuclear power plants, but it’s home to two large military bases: Fort Knox and Fort Campbell.

Hack said Kentuckians can still use their drivers’ licenses to access offices for the Social Security Administration, Veterans Affairs and courthouses. And they can still use their IDs to apply for federal benefits, like Medicare. But if the state is still out of compliance by January 2018, Kentuckians will have to use a passport or passport card to board domestic flights.

“I can tell you we are working really hard to avoid that,” Hack said. “The sky is not falling with the denial of this extension request.”

Democratic U.S. Rep. John Yarmuth said he questions whether Real ID “provides an improved level of security that justifies the costs,” but he said Kentucky “simply can’t ignore the law.”

“It’s unfortunate that Governor Bevin vetoed the bicameral, bipartisan agreement that would have prevented further headaches for Kentucky travelers and residents,” Yarmuth said in a news release.

The state law that Bevin vetoed would have raised the drivers’ license fee to $48 from $20 and made licenses good for eight years instead of four years. It would have also required residents to bring their birth certificates and Social Security cards when renewing their license.

Kentucky drivers’ licenses already meet most of the physical requirements for Real ID. The problem is how Kentucky issues those licenses. State law requires the circuit court clerks to issue drivers’ licenses, meaning Kentucky has 144 offices throughout its 120 counties that issue licenses. Each office would have to upgrade its security and do extensive background checks on its employees.

“At the end of the day if all states are in compliance with this law, the Department of Homeland Security will not have a shred of quantitative evidence to demonstrate to the American people that we are safer than we were before this law was passed,” Hack said. “That’s really unfortunate.”