Norway's King Harald has died aged 89, the palace said on Friday, his 53-year-old son Crown Prince Haakon automatically succeeding him on the throne.
"It is with deep sadness that we announce that His Majesty King Harald passed away today. King Harald passed away peacefully at Oslo University Hospital on Friday, August 28 at 6:35 am," (0435 GMT) it said in a statement.
The flag at the royal palace in Oslo was lowered to half-mast, as crowds streamed to the palace courtyard to pay their respects.
Prime Minister Jonas Gahr Store said he had received the news with "deep sorrow".
File photo: Crown Prince Haakon//AP
"An entire nation mourns, and at the same time remains profoundly grateful for a long life devoted to Norway," he said in a statement.
"King Harald loved Norway. And Norway loved its king."
- 'Down-to-earth' -
Hundreds of flowers had already been laid outside the palace the day before, after it announced the king was in "extremely serious" condition in hospital.
"Of course it's sad. He's a symbol of our country. And naturally, it's sad when something so beautiful comes to an end," 36-year-old Maja Otvik told AFP in front of the palace.
Vigdis Haug, 65, said she had valued Harald's ability to unify people.
"I think he has been such a down-to-earth king who has cared about all of us, and the words he always uses when he gives a speech are so wise and so valuable," she told AFP.
Haug and others AFP spoke to pointed in particular to Harald's speech after the neo-Nazi Anders Behring Breivik claimed 77 lives in twin attacks on July 22, 2011, in Norway's worst massacre since World War II.
Neighbouring Sweden's King Carl XVI Gustaf called him "an outstanding representative of his country. He gave 'All for Norway'," referring to Harald's royal motto.
Denmark's King Frederik meanwhile called the late monarch "an extraordinary man".
The British King Charles III said he mourned the death of his "dear cousin", hailing Harald as a "towering figure".
Harald was also king when the Oslo Accords between Israel and the Palestine Liberation Organization (PLO) were negotiated in the 1990s, and Israeli President Isaac Herzog said he was "deeply saddened" by his passing.
Church bells were to ring across Norway at noon (1000 GMT) to mark the king's passing.
- Succession -
Haakon was to meet with the government at 11:30 am (0930 GMT) to formally inform it of the monarch's death, and to announce the royal name and motto he has chosen.
After that, the flag over the royal palace will be raised to the top again, while another flag on the royal balcony and at other official buildings will remain at half-mast until after Harald's funeral.
Haakon's 22-year-old daughter Ingrid Alexandra also automatically becomes crown princess.
Europe's oldest reigning monarch, King Harald had 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.
The royal family had rushed to his bedside, with media reporting that Haakon kept vigil overnight.
- Turbulent year -
Harald, who ascended the Norwegian throne in 1991, embodied an open and tolerant Norway during his reign.
He faced mounting health problems in his final years, forcing him to have a pacemaker fitted and to scale back his official schedule.
But he always ruled out abdicating, arguing that he took a lifelong oath before the Norwegian parliament.
The past year has been a turbulent one for the Norwegian royal family.
In February, Harald 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.
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 relationship prior to her marriage to Haakon, Marius Borg Hoiby, is also in the spotlight as a result of his 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 status and his unassuming, modest lifestyle.
