WASHINGTON : US airports reported 22 incidents of air traffic controller shortages on Saturday, Transportation Secretary Sean Duffy said, with more shortages expected to bring more flight delays and cancelations in the days ahead as the government shutdown drags on.

According to FlightAware, a flight tracking website, there were more than 5,900 US flight delays by 6 p.m. Eastern Time (2200 GMT) on Sunday and more than 5,300 on Saturday. Delays have often been above average since the shutdown began on October 1.

The state of air safety has been closely watched for signs of increased delays or cancelations, as observers look for indications that the shutdown is making life harder for Americans. That in turn could pressure lawmakers to break the budget deadlock that led to the shutdown.

The Federal Aviation Administration on Saturday had 22 “triggers” that indicated shortages of air traffic controllers, Duffy told the Fox News “Sunday Morning Futures” program. He called that figure “one of the highest that we’ve seen in the system” since October 1.

“That’s a sign that the controllers are wearing thin,” Duffy said. The agency also issued a ground stop at Los Angeles International Airport on Sunday due to traffic controller staffing shortages around 11:30 a.m. (1530 GMT), which was lifted later although delays continued.