Bernie Sanders, the independent US senator who is seeking the Democratic presidential nomination in 2016, was undergoing a medical procedure Monday to repair a hernia, his staff said.
The elective outpatient hernia repair procedure was being performed at George Washington University Hospital, his staff said.
Sanders, who is 74, "will resume his Senate duties on Tuesday," according to a statement from campaign spokesman Michael Briggs.
No information was provided on the specifics of Sanders's case.
A hernia is a condition in which part of an organ protrudes through a cavity wall, such as the intestine bulging through a weak part of the abdominal wall.
Sanders is running second in the polls among the three candidates seeking the Democratic nomination. He trails frontrunner Hillary Clinton, who is six years his junior.
With no apparent health problems, Sanders has campaigned tirelessly since May, including at an event Sunday in New Hampshire.