Two high-ranking deputies are leaving their posts at the Minnesota Department of Human Services, the state's sprawling, $17.5 billion social service agency, in an unexpected move confirmed Thursday by Commissioner Tony Lourey.

The abrupt departure of two veteran administrators sets up an early test of the leadership of Lourey — who lobbied hard for the job after serving in the state Senate for more than a decade — as well as for the new administration of Gov. Tim Walz, who appointed Lourey for the top job. No reasons were given for the near-simultaneous exits.

Claire Wilson, a deputy commissioner who has been with the agency since 2016, will resign as of Aug. 1. She oversees the department's policy, including children and family services, health care, community supports and continuing care, as well as external relations.

Deputy Commissioner Charles Johnson will stay an additional "month or two," according to an internal e-mail. Johnson oversees operations, including the agency's budget and information technology, as well as a large division known as direct care and treatment that oversees programs for people with mental illnesses, developmental disabilities and substance use problems. He also oversaw the state mental hospital in St. Peter and the state sex offender program.

Johnson has served as a deputy commissioner since 2013 and before that was chief financial officer. He's earned a reputation around the State Capitol and social service circles as a master of detail, including the arcane flow of funds between state and federal programs that is necessary to keep the agency afloat.

Neither Johnson nor Wilson were immediately available for comment Thursday.

The two resignations come at a challenging time for the agency. DHS has been under increased pressure from lawmakers to rein in spending and crack down on fraud in state-licensed programs, while simultaneously meeting the care needs of the state's expanding population of poor, elderly and frail people in the state's Medical Assistance program. The state has also struggled to meet a burgeoning demand for home care services amid a severe shortage of care workers.

In March, the agency's inspector general in charge of investigating fraud in state health and welfare programs was placed on leave after the legislative auditor found high levels of fraud in the state's child-care assistance program.

"This is the exact time that we need strong leadership," said Roberta Opheim, state ombudsman for mental health and developmental disabilities.

Sen. Jim Abeler, chairman of the Human Services Reform Finance and Policy Committee, said he was told the departures stemmed from "internal personality conflicts" between top administrators at DHS, which surfaced after Lourey was appointed to head the agency in January.

"This is tragic because it creates a huge leadership gap at the top of our state's largest agency," Abeler said. "Replacing their knowledge and expertise and the relationships they've established will be very difficult."

The agency serves 1.2 million Minnesotans. It manages programs such as Medical Assistance, which is Minnesota's version of the state and federal program to provide health insurance to the indigent and people with disabilities, including the elderly.

Lourey released a brief statement thanking his deputies for their service. "Their guidance, leadership and wisdom was invaluable during the legislative session," he said.

Johnson and Wilson join Dr. Jeffrey Schiff in their departure. Schiff was the longtime medical director for the Medical Assistance program until his job was eliminated last month.

"Their simultaneous and unexplained departures along with the reorganization that led to my dismissal points to some systemic leadership issues that need to get addressed by the governor," Schiff said. "Minnesotans who are served by [Medical Assistance] are not being served well when people like this are departing."

Sen. Michelle Benson, R-Ham Lake, who chairs a key health care committee, also said she's concerned. "That's significant institutional knowledge that can't be replaced," she said.

Benson said Johnson is in the midst of doing important work on the agency's information technology — specifically its platform for determining whether Minnesotans are eligible for various social service programs. He also was overseeing the Office of Inspector General.

Wilson, Benson said, was interested in pediatric, adolescent and adult mental health and pushed hard for an item in the budget that Walz signed about six weeks ago.

"I hope they continue to move those important programs forward," Benson said.

Staff writer Glenn Howatt contributed to this report. J. Patrick Coolican • 651-925-5042 Chris Serres • 612-673-4308