Mail carriers with the U.S Post Office are working around the clock to get last-minute Christmas cards and packages where they need to be in time for the holiday.

At the McAllen Post Office, hundreds of employees are working together to round up thousands of packages to be delivered before Christmas Day. 

U.S. Postal Service (USPS) estimates they'll deliver more than 12 billion letters, cards and packages nationwide during their peak season, between Thanksgiving Day and New Years Day. 

McAllen Postmaster Linda Cordova says carriers will not make deliveries on Christmas Day. 

"If there are additional packages, I do plan to get those out tomorrow," Cordova said. "And deliver as late as 8 o'clock being my latest." 

If you find yourself shopping for gifts last minute that need to be shipped out, the McAllen branch will be open until 7 p.m. on Dec. 24, and express shipping will still be available. 

Watch the video for the full story.