Erroll Southers announced Monday that he will step down as assistant police chief at Los Angeles International Airport by the end of March, just two months after he withdrew his nomination to head the Transportation Security Administration.

Southers, a former FBI agent, has served two years as assistant chief of intelligence and emergency operations for Los Angeles World Airports, the city agency that operates LAX.

He said he plans to enter the private sector as a security consultant and expand his teaching duties at USC's National Homeland Security Center for Risk and Economic Analysis for Terrorism Events (CREATE).

"It's like fast-forwarding my life by three years," Southers said. "I did not expect to get the kind of attention that I got when I withdrew my nomination with the TSA, but I'm very excited and obviously the airport is going to remain a prime concern for me."

President Barack Obama nominated Southers last summer to serve as the TSA's fifth administrator in eight years. Southers withdrew his nomination on Jan. 20 amid fierce opposition from Republicans, who had expressed concern that an estimated 50,000 TSA security screeners across the country would join unions under Southers' leadership.

Additionally, Southers had come under fire for ordering criminal background checks on the boyfriend of his estranged wife about 20 years ago. In a letter delivered to the U.S. Senate, Southers said he regretted the incident while serving as an FBI agent and that he was censured by his superiors.

"I want to thank the men and women of the Airport Police Department because if it wasn't for them, I wouldn't have become a nominee," Southers said. "I was the lucky one to be nominated by the president, but everyone should know that Washington, D.C., looks at us a model for homeland security and we should be proud of that."

Southers has more than 30 years of experience in law enforcement and homeland security issues. He previously worked as a detective for the Santa Monica Police Department and served as deputy director of the Governor's Office of Homeland Security.

"The fact he is leaving creates a void and we're hoping that there will be a wide search to replace someone of his caliber," said Marshall McClain, president of the Los Angeles Airport Peace Officers Association, which represents 435 police officers and firefighters at LAX.

"I know it will be difficult," McClain said. "But it will be a great loss to the intelligence community here at LAX."