Bahrain's crown prince, Sheikh Salman bin Hamad al-Khalifa, was appointed prime minister on Wednesday after the death of his great uncle, who had held the post since independence in 1971.
The new premier, Crown Prince Sheikh Salman bin Hamad Al Khalifa, 51, has been viewed as the ruling family's leading proponent of social and economic reforms, although some changes were blocked in years past by family hardliners.
Prince Khalifa bin Salman al-Khalifa, the world's longest-serving prime minister, died at the age of 84 while undergoing medical treatment in the United States, state media announced.
Prince Khalifa was a controversial figure during his five decades in office, accused of opposing reforms and cracking down on activists. He was also deeply unpopular with the Sunni-ruled kingdom's Shiite population.
When Shiite-led protesters occupied Manama's Pearl Square for a month in 2011, before being driven out by Saudi-backed security forces, their main demand was for Prince Khalifa to step down.
His successor, who is from a new generation of Western-educated Gulf leaders, has instead tried to build bridges with opponents.
After studies in the United States and Britain — including a master's degree from Cambridge University — he has served as first vice prime minister and is deputy supreme commander of the Bahrain Defence Force.
King Hamad issued a royal decree appointing his son as head of the Council of Ministers with immediate effect, the Bahrain News Agency said.
Prince Khalifa's burial will take place after his remains have been transported home, and in line with novel coronavirus restrictions, only a limited number of relatives will attend.
The country will hold a week of official mourning, during which flags will be flown at half-mast. Government ministries and departments will be closed for three days.
Gulf leaders paid tribute, hailing the veteran leader's long career "that has shaped Bahrain's recent history", according to Dubai ruler Sheikh Mohammed bin Rashid Al-Maktoum.
Targeted by protesters
Prince Khalifa played a key role in Bahrain's political and economic affairs, including setting the stage for a referendum that put paid to the Shah of Iran's claims to the tiny Gulf archipelago.
Born on November 24, 1935, he began to attend his father's royal court at the age of seven along with his elder brother, Prince Issa.
He was named in 1970 as the head of the state council, the executive branch of government which became the council of ministers after independence from Britain.
He conducted difficult negotiations with the Shah of Iran, Mohammad Reza Pahlavi, before independence, over Shiite Iran's claims to Bahrain's chain of islands.
A referendum to determine the country's future resulted in an overwhelming vote in favour of independence under the rule of the Sunni Al-Khalifa dynasty, despite the large Shiite population, the size of which is disputed by the government to this day.
Prince Khalifa strove for many years to establish Bahrain as a regional financial hub. Unlike other Gulf states, the kingdom has only modest oil resources.
Working closely with his brother, the late emir Sheikh Issa bin Salman Al-Khalifa, he favoured strong ties with Washington.
Those relations have continued to grow, with Bahrain now hosting the US Navy's Fifth Fleet as one of Washington's most trusted allies in the region.
History of unrest
Political unrest has simmered in Bahrain since independence, but following Iraq's 1990 invasion of Kuwait, it witnessed renewed pro-democracy protests coupled with pressure from the United States and Britain.
Shiite-led demonstrations intensified in 1994, with protesters demanding the restoration of an elected parliament, the return of political exiles and a more equitable distribution of wealth.
The unrest, which claimed at least 38 lives, lasted until 1999, when King Hamad — the son of Sheikh Issa — ascended the throne and initiated reforms, which turned Bahrain into a constitutional monarchy and reinstated the elected parliament.
But protesters were back on the street in February 2011, taking their cue from Arab Spring uprisings, demanding a "real" constitutional monarchy, with an elected premier to replace Prince Khalifa.
Although the government quelled the protests after one month, the country continues to face political repression, with several opposition chiefs behind bars. At least 89 people were killed in the unrest.