U.S. Senator Maria Cantwell joined a Mississippi Republican in asking the TSA not to remove screeners from airports for deployment to the US-Mexico Border.

Cantwell joined Sen. Roger Wicker in sending a letter to TSA leaders expressing concern over the plan.

This comes at the start of a busy weekend of travel for Memorial Day. Sea-Tac Airport expects upwards of 500,000 passengers over into the holiday weekend.

The Port of Seattle previously expressed concern over losing any TSA staff. Managing Director Lance Lyttle testified before lawmakers that Sea-Tac already struggles to retain TSA agents, and losing any could lead to “lines out to our parking garage as often as 4 to 5 days a week.”