The Japan Times - Norway's King Harald, 89, in 'extremely serious' condition

Queen Sonja and 53-year-old Crown Prince Haakon, who is acting as regent during his father's illness, have cancelled all royal engagements, said a palace statement. Norwegian media said they were at the king's bedside.

Europe's oldest reigning monarch has been in hospital in Oslo since August 17 suffering from haemolytic anaemia, a condition caused by an abnormally rapid destruction of red blood cells which leads to fatigue and shortness of breath.

"His Majesty the King's health condition is extremely serious," the palace said, providing no specific details.

Norwegian media showed images of the queen, Haakon and his wife Mette-Marit arriving at the hospital.

Norwegian Prime Minister Jonas Gahr Store said in a comment to AFP that he was "deeply affected" by the news.

"I stand together with the entire country as we now send our warmest thoughts to the king and the rest of the royal family. I am confident that the king is being well taken care of, and that he is receiving good and compassionate treatment," he said.

Following the palace announcement, Norway's bishops cut short a study visit to Rome where they met with Pope Leo and were to return to Norway Thursday, according to Christian newspaper Vart Land.

Harald was admitted to Oslo University Hospital due to fluid retention from cortisone treatment he was receiving.

The palace said on Sunday that he was receiving antibiotics for a bacterial infection in his blood and that he had responded to the treatment.

Harald, who ascended the Norwegian throne in 1991, has had multiple health problems in recent years, forcing him to have a pacemaker fitted and to scale back his official schedule.

But he has always ruled out abdicating, arguing that he took a lifelong oath before the Norwegian parliament.

- Turbulent year -

In February, he was hospitalised for an infection and dehydration in Tenerife, where he was on a private trip with Queen Sonja.

His wife, also 89, was briefly admitted to hospital in May due to heart problems.

Harald's health woes come at a turbulent time for the Norwegian royal family.

Haakon's wife Mette-Marit is under scrutiny for her ties to the late US sex offender Jeffrey Epstein.

Documents published in January in the United States revealed her sustained and at times intimate correspondence with Epstein between 2011 and 2014, at a time when the American financier had already been convicted.

Mette-Marit's son from a previous marriage, Marius Borg Hoiby, is also in the spotlight as a result of legal troubles.

He was sentenced in June to four years in prison for two rapes and 32 other charges, including violence against a former partner. He has appealed the verdict.

Suffering herself from a serious lung disease, Mette-Marit, 53, had to undergo a lung transplant in July.

The royals remain broadly popular with the Norwegian public, in large part to Harald's unifying figure and his unassuming, modest lifestyle.

Y.Watanabe--JT