STOCKHOLM (AP) — King Harald V of Norway has been hospitalized with an infection while on vacation in Malaysia, the Norwegian royal house said in a statement Tuesday.

The 87-year-old monarch has had several illnesses in recent months, raising concern about the head of state’s health. But royal officials have told Norwegian media that Crown Prince Haakon will be carrying out his planned engagements at home.

Harald, who is on a private trip abroad, is the oldest monarch in Europe. Two days before his birthday last week, the palace announced that the king would be undertaking a private trip abroad, without specifying the destination or dates, according to the Norwegian news agency NTB.

Norwegian Prime Minister Jonas Gahr Støre said that he was “sad” to hear of the king’s hospitalization and wished him a “speedy recovery,” NTB said.