Chad Wolf is resigning as the acting secretary of Homeland Security, he announced in a letter to the department Monday obtained by CNN.
Wolf's resignation comes amid heightened security concerns in the wake of the US Capitol attack and just days before the transition in administrations.
"I am saddened to take this step, as it was my intention to serve the Department until the end of this Administration," Wolf said.
Pete Gaynor, the administrator for the Federal Emergency Management Agency, will be the acting secretary, Wolf said.
Wolf, who served in the post for 14 months, is the latest Cabinet secretary to resign in recent days, though it's unclear whether it's directly related to last week's riots. Betsy DeVos, who served as education secretary, and Elaine Chao, who served as transportation secretary, have also resigned.