WASHINGTON — Attorney General Merrick Garland will undergo back surgery this weekend and temporarily hand over his official duties to his deputy, the Justice Department announced Monday.

A Justice Department spokesperson described the medical procedure, scheduled for Saturday, as “minimally invasive” but said it will require Garland, 71, to be under general anesthesia for about 90 minutes, during which Deputy Attorney General Lisa Monaco will assume his duties.

“The delegation of his duties will go to the Deputy Attorney General shortly before the procedure, during the procedure, and for a brief period following the procedure to allow for recovery from general anesthesia,” Public Affairs Director Xochitl Hinojosa said in a statement.

Defense Secretary Lloyd Austin faces a congressional investigation for initially having kept secret his hospitalization over complications that resulted from treatment for prostate cancer. He and his staff waited three days to inform the White House, top national security officials and even some high-ranking defense officials. He was released from the hospital on Jan. 15 after two weeks and returned to the Pentagon on Monday.

Hinojosa said the surgery Garland will undergo is called an interlaminar decompression to address stenosis in his spine. It is essentially aimed at reducing pain in the lower back.

“The Attorney General is likely to go home the same day” as the procedure and “will return to work the week of February 5th,” Hinojosa said.

Michael Kosnar reported from Washington and Dareh Gregorian from New York.