COLUMBIA, S.C. (WCIV/AP) -- The embattled head of the state's Department of Social Services handed in her resignation Monday morning.
The move comes a day before senators planned to take up a no-confidence resolution on her leadership.
Koller's letter said it's become increasingly apparent that she's causing a distraction that's making it more difficult for DSS to continue improvements made at the agency during her tenure.
"Lillian Koller is a dedicated public servant and child advocate, and a wonderful and loving mother - and I am so grateful for her service to South Carolina," said Gov. Nikki Haley. "Under her leadership, DSS closed a $28 million deficit, moved more than 20,000 South Carolinians from welfare-to-work, and has done wonders to improve our foster care system, placing more South Carolina children in stable, healthy families."
Haley went on to say that the state was lucky to have Koller's leadership, adding that she is proud of Koller and her work at DSS, "and most of all, that I can call her my friend."
Amber Gillum, Deputy State Director for Economic Services, will serve as the interim director until a permanent appointment is made by the governor.
Her resignation comes a day before the Senate was expected to debate a bi-partisan measure saying the agency under Koller's leadership has failed to protect the state's abused and neglected children.
Also this week, Koller was to testify a third time before a Senate panel investigating problems at the agency.
House Democratic Leader Rep. Todd Rutherford said Koller's resignation was long overdue.
"Governor Haley's insistence on standing by her failed agency head kept hundreds of South Carolina children at risk of abuse, neglect, and even death," he said in a statement. "Ultimately this isn't about Lillian Koller, it's about the lack of leadership and accountability at both DSS and the Governor's office that must be fixed. There is still much work left to do to assure the people of South Carolina that the Department of Social Services is under control and functional. Now the real work begins."
Haley has repeatedly backed Koller, despite calls for her ousting.