(LEWES, Del.)- The Transportation Security Administration moved dramatically Monday to address the issue of long lines at the nation's airports, replacing its head of security and creating a centralized incident command team at TSA headquarters.

Kelly Hoggan, the agency's assistant administrator for security operations since 2013, will be replaced by Darby LaJoye, TSA Administrator Peter Neffenger said in an internal memo obtained by NBC News.

LaJoye, currently a deputy assistant TSA administrator, was previously a top security official at two of the world's busiest airports - Los Angeles International Airport and JFK in New York.

Hoggan, who has been the focus of congressional inquiries into staffing and pay decisions, was reassigned to new duties, Neffenger said.

The appointment is part of a series of moves, some of them not revealed until Monday, that Neffenger has taken since hundreds of passengers were stranded in security lines as their planes took off at Chicago's O'Hare International Airport this month.

Neffenger and his boss, Homeland Security Jeh Johnson, promised that more than 300 extra TSA officers would be assigned to Chicago's airports by mid-August - 58 of them within the next three weeks - and that 100 more part-time workers in Chicago would be promoted to full time.