GENEVA >>  U.S. Secretary of State John Kerry broke his leg in a bicycle crash Sunday after striking a curb, and scrapped the rest of a four-nation trip that included an international conference on combating the Islamic State group.

Kerry was in stable condition and in good spirits as he prepared to return to Boston for further treatment with the doctor who previously operated on his hip, U.S. State Department spokesman John Kirby said. He said X-rays at a Swiss hospital confirmed that Kerry fractured his right femur.

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

Kerry, 71, was taken by helicopter to Geneva’s main medical center, HUG, after hitting a curb with his bike near Scionzier, France, about 40 kilometers southeast of the Swiss border.

Paramedics and a physician were on the scene with his motorcade at the time and provided him immediate attention. They quickly decided to order the 10-minute-long helicopter transport.

The Dauphine Libere, a local newspaper, said Kerry fell near the beginning of his ride to the famed mountain pass called the Col de la Colombiere, which has been a route for the Tour de France more than a dozen times.

Right around the time of his fall, a Twitter feed about local driving conditions warned of the danger due to gravel along the pass. But U.S. officials said there was no gravel on the road where the accident occurred. According to the newspaper, some Haute Savoie officials were with Kerry at the time, including the head of the region.

Kerry’s regular plane was returning to the United States carrying much of his staff and reporters who accompanied on the trip.

The secretary of state planned to fly back late Sunday aboard a plane with special medical equipment “to ensure he remains comfortable and stable throughout the flight,” Kirby said. “Its use is nothing more than a prudent medical step on the advice of physicians.”

Kerry’s cycling rides have become a regular occurrence on his trips. He often takes his bike with him on the plane and was riding that bicycle Sunday.

During discussions in late March and early April between world powers and Iran, Kerry took several bike trips during breaks. Those talks were in Lausanne, Switzerland, and led to a framework agreement.

Kerry had been in Geneva for six hours of meetings with Iranian Foreign Minister Mohammad Javad Zarif on Saturday as the sides now work to seal a comprehensive accord by June 30.

The prospect of a lengthy rehabilitation could hamper the nuclear talks and other diplomatic endeavors. Even if Kerry does not need surgery, it was not immediately known when he could fly again after returning to the United States.

Kerry has been the lead negotiator in several marathon sessions with Iran going back to 2013. The injury could affect other potential trips, such as one to the Cuban capital to raise the flag at a restored U.S. Embassy.

As for the current trip, Kerry had planned to travel to Madrid on Sunday for meetings with Spain’s king and prime minister, before spending two days in Paris for an international gathering to combat IS.

He will participate in the Paris conference remotely, Kirby said.

Kerry decided to seek treatment at Massachusetts General Hospital because the fracture is near the site of his earlier hip surgery, Kirby said.