Transportation Secretary Sean Duffy warned that his agency might have to close sections of the U.S. airspace next week due to the ongoing government shutdown, citing a lack of air traffic controllers.

Speaking to reporters on Tuesday, Duffy said that if the government isn’t reopened soon, there will be “mass chaos” including flight delays, flight cancellations, and the closure of airspace in some areas.

The secretary said that a week from Tuesday, “you may see us close certain parts of the airspace” because “we just cannot manage it, because we don’t have the air traffic controllers.”

“With this shutdown, it would be dishonest to say that more risk is not injected into the system. There is more risk in the system,” he said.

U.S. aviation has already faced tens of thousands of flight delays over the last month. The comments represented the Trump administration’s direst warning of impending impacts from rising air traffic controller absences.

As the government shutdown entered its 35th day, the Federal Aviation Administration (FAA) delayed a new round of flights on Tuesday. Airlines also said this week that 3.2 million passengers have been hit by delays or canceled flights due to a spike in air traffic controller absences.

On Tuesday, there were more than 2,300 flight delays as the FAA imposed postponements in Phoenix and expected to delay flights in Houston after identifying staffing issues in Denver, Detroit, and elsewhere, according to FlightAware.

Air traffic controllers missed their first paycheck last week, Duffy said, adding that some have been forced to take second jobs to “put food on their table, to put gas in their car” during the shutdown.

“A lot of us can navigate missing one paycheck. Not everybody, but a lot of us can. None of us can manage missing two paychecks,” he told reporters.

The shutdown was initiated on Oct. 1 as members of Congress could not come to an agreement on a stopgap measure to fund the government, forcing the Trump administration to furlough thousands of workers, suspend the work of certain agencies, and pause some programs.

Democrats blame Republicans for not negotiating with them to reopen the government and have said that a continuing resolution should include an extension of health care subsidies that are set to expire at the end of the year. Republicans have accused Democrats of holding the government hostage and say that the government should be reopened before health care policy discussions.

This week, President Donald Trump called on Republicans to terminate the Senate filibuster rule in order to pass a bill to reopen the government as well as fund other parts of his administration’s agenda.

“Elections including the Midterms, will be rightfully brutal. If we do terminate the Filibuster, we will get EVERYTHING approved, like no Congress in history,” Trump stated in a post on Truth Social.

In response, Senate Majority Leader John Thune (R-S.D.) told reporters that not enough Senate Republicans would vote to end the filibuster, which requires 60 votes to overcome.

In 2019, widespread disruptions in air travel pressured lawmakers into ending a 35-day government shutdown during Trump’s first term in office.

Reuters contributed to this report.