Erroll Southers is resigning his job as assistant police chief of Los Angeles World Airports, said an AP report.

In a letter, he wrote that he will leave the post on March 27 to seek new challenges. He helped oversee 1,200 officers at Los Angeles International, Ontario International and Van Nuys airports. Airport spokeswoman Nancy Castles says he wasn't asked to leave.

 

Southers was nominated by President Obama to head the TSA but came under fire from Republicans concerned that he would unionize the agency. He withdrew his nomination in January.