Transportation Secretary Sean Duffy has warned that air traffic controllers are feeling increasing pressure at work amid the government shutdown for which Republicans and Democrats are both holding each other responsible.

Air traffic controllers would have typically received their next paycheck on Oct. 14, Duffy said, but they will now not be paid until the government reopens. An estimated 13,000 air traffic controllers and 61,000 TSA staff are expected to continue working without pay throughout the shutdown.