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The Transportation Security Administration is flooding Chicago's O'Hare International Airport with more staff and resources after hundreds of passengers were stranded as their planes took off while they waited in line, local and federal authorities said Tuesday.

TSA Administrator Peter Neffenger apologized at a travel conference Tuesday in Houston to the more than 450 passengers who didn't make it onto their flights overnight Sunday and Monday as the security screening lines crept along at O'Hare.

"We had a significant challenge in Chicago yesterday," Neffenger said. "I don't know what that was, but fixing that, that is of great concern to me.

"I always tell people I won't apologize for doing our job well, but I do apologize to the people who found themselves stranded in Chicago yesterday," Neffenger said.

Neffenger and his boss, Homeland Security Jeh Johnson, promised Chicago Mayor Rahm Emanuel on Tuesday that more than 300 extra TSA officers will be assigned to Chicago's airports by mid-August — 58 of them within the next three weeks.

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One hundred more part-time workers in Chicago will be promoted to full time, Emanuel said.

"The TSA wait times at Chicago's airports have been unacceptable," Emanuel said. "There is no excuse for passengers to wait in line for hours."

Other measures that Emanuel said the feds promised include the tripling of authorized overtime, the addition of at least five more canine teams and the diversion of operational experts to Chicago from airports around the country.

Related: Chicago Airport's Nightmare TSA Lines Could Play Out Nationally This Summer

But that wasn't good enough for Sen. Mark Kirk, R-Illinois.

"The flying public is experiencing a high security risk and economic burden from unnecessary wait times and missed flights due to insufficient staffing at TSA," Kirk said in a statement Tuesday.

"If travelers do not have relief by Memorial Day, TSA Administrator Neffenger must resign and be replaced with a leader who can provide fast and secure screening," he said.

The TSA confirmed the reallocations to NBC News on Tuesday evening. They're among the first new measures among a long list of fixes that Johnson, the Homeland Security secretary, outlined at a news briefing — including the hiring of more than 750 new screening officers across the country.

Among the measures likely to be most controversial, the TSA will also strongly encourage airlines to find ways to reduce the size and number of carry-ons, the screening of which Johnson said "has a lot to do with the wait time."

Checked baggage is easier and more efficient to handle, he said. But fees for checking extra bags are among the most frequently cited complaints that passengers already have about airlines.

"No, it's not a permanent solution," Johnson said. But "no one should have to wait three hours to get to the gate."

TRAVELERS: @TSA checkpoints are experiencing longer than avg wait times. We recommend arriving 3hrs prior to flights https://t.co/eFNeugkRD8 — O'Hare Intl. Airport (@fly2ohare) May 17, 2016

Even the White House weighed in, as press secretary Josh Earnest acknowledged that Chicago screeners face a "significant challenge."

"They don't want to inconvenience people," Earnest said at the daily White House news briefing. But aviation officials "want to make sure [people] they can engage in travel safety."