(CNN) Seeking to ease the pain of airport security agents working through the partial government shutdown, the Transportation Security Administration is compensating those on duty the day after the lapse in funding and awarding $500 bonuses for work during the holiday travel season.

TSA Administrator David Pekoske announced the compensation Friday on Twitter amid mounting concerns that the nation's airports might not be able to provide the usual standard of security. Already, hundreds of TSA screeners from at least four major airports have called out from their shifts since the shutdown began three weeks ago.

Pekoske said all TSA employees who worked December 22, the last day in that pay period, will receive pay for the day no later than Tuesday. They didn't get paid originally because the day started after the shutdown began.

The $500 bonuses for uniformed screening officers who worked during the busy holiday travel season should arrive in the coming days, Pekoske tweeted.

The administrator said the pay was possible due to "unique authorities provided TSA in law."