King Bhumibol Adulyadej, long a unifying figure in politically fractious Thailand, died Thursday and uncertainty over the succession quickly arose as his crown prince reportedly sought a delay in taking over.
The death of the 88-year-old Bhumibol, the world's longest-reigning monarch, removed a revered father figure in a country where political tensions are still raw two years after a military coup.
US President Barack Obama led global tributes to Bhumibol, whose death ends a remarkable seven-decade reign during which Thailand served as a pillar of relative stability in a turbulent region.
Crown Prince Maha Vajiralongkorn, 64, is the king's named successor, but the country's military junta chief Prayut Chan-O-Cha said the prince informed him he was not yet ready to assume the throne.
"He asked for time to prepare for legal processes in order to proclaim him on the throne at the appropriate time," Prayut told reporters after meeting the prince.
Most Thais have known no other monarch than Bhumibol and he was portrayed as a guiding light through decades of political turmoil and coups.
The palace said he died at 3:52 pm (0852 GMT) after a long illness, causing large crowds to erupt in mourning outside the hospital where Bhumibol spent most of the last two years.
"How will Thailand live without you, father?" cried one distressed young man as others chanted "Long Live the King!"
Prayut, the former army chief who heads the ruling junta, quickly affirmed Vajiralongkorn as chosen successor.
But the delay in officially proclaiming him king will fuel concerns over a potentially messy succession.
The Crown Prince is yet to attain his father's widespread popularity, spending much of his time overseas.
Analysts said elites likely want to stage a slow and careful transition.
"But any delay is worrisome as it creates suspicion and the Thai people are concerned anyway about the monarchy's future under Vajiralongkorn," said Paul Handley, author of the unauthorised biography "The King Never Smiles".
"It's maybe too early, but it almost creates a power vacuum."
- Year-long mourning -
Speaking earlier on television, Prayut said Thailand would hold a one-year mourning period and that the country's notorious entertainment functions must be "toned down" for a month.
Trading on the Thai stock exchange would continue, however.
Bhumibol's death is a major test for Prayut's junta, which seized power in 2014.
The coup ended a decade of strife between Thailand's two major political factions, exacerbated by the king's declining health as jostling elites competed for power.
The military has deep links with the palace and many inside the kingdom saw the putsch as a move to ensure generals could squelch any instability during a succession.
Backed by a palace-driven personality cult, Bhumibol was revered by many as a demigod who rose above the kingdom's notoriously fractious politics, and many mourners on Thursday fretted about the future.
Bhumibol's subjects have had many years to contemplate his demise -- he has not been seen in public for months and has suffered prolonged ill health -- but his passing remained a great tragedy to millions.
During his reign, Thailand transformed from an impoverished, rural nation into one of the region's most successful economies, avoiding the civil wars and communist takeovers of its neighbours.
He built a reputation for criss-crossing the nation to visit the rural poor and sometimes intervened to quell Thailand's frequent political violence.
At other times, however, he stayed silent. He approved most of the army's many coups during his reign.
In a statement Obama described Bhumibol as a "close friend" and "tireless champion" of his country's development. UN Secretary General Ban Ki-moon said he was a "unifying national leader... respected internationally".
- Criticism muted -
Any criticism, republican sentiment, or speculation on succession is smothered by a draconian lese majeste law, use of which has surged since the military’s latest takeover.
In recent years, and especially since the 2014 coup, the heir-apparent Vajiralongkorn has been more visible in Thailand and appeared in more royal engagements.
He will inherit one of the world's richest monarchies.
During his reign, Bhumibol, with his establishment allies, built up a multi-billion-dollar royal business empire spanning property, construction and banking.
The palace's announcement this week that the king was gravely ill sent stocks and the currency tumbling.
Capital Economics said in a note that the king's death could lead to "deep political uncertainty".
"There is a risk that political tensions flare up, triggering a slowdown in economic growth," it said. "All eyes now will turn to the succession process."