WASHINGTON - Wait times at US airport security checkpoints have reached the longest levels in the 24-year history of the Transportation Security Administration (TSA) amid the prolonged Department of Homeland Security (DHS) shutdown, with some exceeding four hours, a senior official said Wednesday.

Several major airports are seeing absenteeism rates of 40 to 50 percent among TSA workers, Acting TSA Administrator Ha Nguyen McNeill told a House Homeland Security Committee hearing.

"This level of disruption is unprecedented and unacceptable, and significantly undermines the security of US transportation systems," McNeill said.

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She added that many workers are struggling to cover basic expenses, with some unable to pay utility bills and facing service shutoffs. Others have received eviction notices, are sleeping in their cars, or are selling blood and plasma to make ends meet.

Since the shutdown began in mid-February, more than 480 TSA employees have resigned, she said.

As major airports continue to face hours-long security lines due to staffing shortages during the shutdown, Democrats and Republicans traded blame on Wednesday.

"Senate Republicans have now blocked TSA funding 9 times. They are solely responsible for the chaos travelers are experiencing," Senate Minority Leader Chuck Schumer wrote on X.

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US President Donald Trump, meanwhile, criticized Democrats, writing on Truth Social, "Blame the Democrats for the Airport's mess. They want our Country to do badly. They want our Country to fail."

The standoff follows Democratic calls for reforms to Immigration and Customs Enforcement after fatal shootings of two US citizens by federal agents in Minneapolis in January. Republicans have rejected those demands, leading to a deadlock that allowed DHS funding to lapse on Feb 13.