People wearing protective masks walks through Hartsfield-Jackson Atlanta International Airport.
CNN  — 

The Transportation Security Administration will extend its US federal transportation mask mandate through January 18, the agency confirmed late Tuesday afternoon.

The mandate was set to expire on September 13. TSA said the purpose of the mask directive is “to minimize the spread of Covid-19 on public transportation,” and the extension comes as Covid-19 cases have skyrocketed in the United States in recent weeks because of the spread of the Delta variant.

More than 2,867 incidents of passengers violating the federal mask mandate have been reported to the Federal Aviation Administration so far this year, the FAA said Tuesday.

The news agency Reuters first reported the mandate extension.

“The emerging evidence about the Delta variant demonstrates it is more formidable than the original virus. Delta spreads more than twice as easily from one person to another, compared with earlier strains,” the US Centers for Disease Control and Prevention said in a statement Tuesday.

“In contrast to the Alpha strain, new data show that fully vaccinated people who are infected with the Delta variant might be infectious and might potentially spread the virus to others.”

The CDC urged that people wear well-fitting masks that cover the nose and mouth in indoor public areas and that unvaccinated people get their shots.

Association of Flight Attendants-CWA President Sara Nelson, representing nearly 50,000 flight attendants at 17 airlines, said she supports the TSA’s extension of the mask mandate.

Flight attendants have been on the front lines of enforcing the requirement.

The decision, she said, “will help tremendously to keep passengers and aviation workers safe.”

“We all look forward to the day masks are no longer required but we’re not there yet.”

This story has been updated with additional information and reaction.

CNN’s Virginia Langmaid and Forrest Brown contributed to this report.