GENEVA — U.S. Secretary of State John Kerry plans to fly to Boston Monday after staying overnight in a Swiss hospital to receive treatment for a broken leg incurred in a bicycle crash. It was unclear how long he will be grounded once he returns to the U.S.

Kerry fractured his right femur Sunday when he struck a curb with his bicycle and fell on a regular Tour de France route about 40 kilometers (25 miles) southeast of Geneva.

Kerry was in stable condition and was receiving treatment at Geneva’s main medical center, HUG. He was to receive further care at Massachusetts General Hospital once he returns home.

“It was sensible for him to remain in the hospital for observation overnight for purely precautionary measures,” U.S. State Department spokesman John Kirby said. “The secretary continues to be in great spirits and active. He has done a range of phone calls including with the president.”

He “never lost consciousness, his injury is not life-threatening and he is expected to make a full recovery,” Kirby said in an earlier statement.