LANGKAWI, Malaysia (AP) — An airplane believed to be carrying Norway’s King Harald departed Malaysia on Sunday, a day after he was implanted with a pacemaker.

Europe’s oldest reigning monarch was hospitalized in Malaysia for an infection during a private vacation in the northern resort island of Langkawi, the royal house said Tuesday.

He underwent surgery at the Sultanah Maliha Hospital on Saturday to implant a temporary pacemaker due to a low heart rate, according to the royal house.

Norwegian media outlets said Harald traveled to the Malaysia with his wife, Queen Sonja, to celebrate his 87th birthday.

A Scandinavian Airlines medical evacuation plane, which took off from Oslo on Thursday, arrived in Langkawi on Friday. The Boeing 737-700 aircraft has previously been used as a flying ambulance.

According to Flightradar24, the same plane departed from Langkawi on Sunday headed for Sharjah in the United Arab Emirates, before it is scheduled to travel onward to Norway.

The aging Norwegian monarch has suffered from frail health over the past few years, and has been admitted to a hospital for treatment on numerous occasions. Harald, who has been seen using crutches, had an operation to replace a heart valve in October 2020 after being hospitalized with breathing difficulties.

Harald has repeatedly said he has no plans to abdicate, unlike his second cousin Queen Margrethe II of Denmark, who stepped down earlier this year. The heir to the Norwegian throne, Crown Prince Haakon, has stepped in and taken over his father’s duties while he’s hospitalized.

Harald’s duties as Norway’s head of state are ceremonial and he holds no political power. He ascended to the throne following the death of his father, King Olav, in 1991.

The country’s first native-born king since the 14th century, he married a commoner as a prince and won hearts in his egalitarian country by leading the mourning in 2011 for the victims of mass killer Anders Behring Breivik.