Saudi Arabia's 84-year-old ruler King Salman was admitted to hospital in Riyadh Monday for gall bladder inflammation, the royal court said, prompting the postponement of the Iraqi prime minister's high-profile visit.

It is rare for Saudi Arabia to report on the health of the ageing monarch, who has ruled the top oil exporter and the Arab world's biggest economy since 2015.

King Salman is the second reigning monarch in the Gulf to be hospitalised after Kuwait's 91-year-old emir Sheikh Sabah al-Ahmad Al-Sabah was admitted to hospital last week, at a time when the region is gripped by the twin crises of the coronavirus pandemic and a plunge in crude prices.

Saudi Arabia's King Salman was admitted to the King Faisal specialist hospital for tests related to gall bladder inflammation, according to the official Saudi Press Agency
Saudi Arabia's King Salman was admitted to the King Faisal specialist hospital for tests related to gall bladder inflammation, according to the official Saudi Press Agency Saudi Royal Palace / Bandar AL-JALOUD

A Saudi royal court statement said King Salman was "admitted today to King Faisal specialist hospital in Riyadh for some medical tests due to cholecystitis," inflammation of the gall bladder.

The statement released by the official Saudi Press Agency around 4:30 am (0130 GMT) did not disclose any further details.

Iraqi Prime Minister Mustafa al-Kadhemi's scheduled visit to Saudi Arabia, which was due to start on Monday, has been postponed after the king's hospitalisation, according to the Saudi foreign minister.

Crown Prince Of Saudi Arabia Mohammad bin Salman (R), pictured here during a US visit, is widely seen as the de facto ruler
Crown Prince Of Saudi Arabia Mohammad bin Salman (R), pictured here during a US visit, is widely seen as the de facto ruler GETTY IMAGES NORTH AMERICA / ALEX WONG

"In recognition of the extremely important visit and a desire to make it a success, our wise leadership in coordination with our brothers in Iraq have decided to postpone the visit" until the king leaves hospital, Foreign Minister Prince Faisal bin Farhan wrote on Twitter.

Hours before Kadhemi was to set off on his first trip abroad as premier, his office said they heard King Salman was suffering from "a sudden health issue".

"It was decided to postpone the visit to the earliest possible date agreed upon by the two sides," his office said in a statement.

A scheduled visit to Saudi Arabia by Iraqi Prime Minister Mustafa al-Kadhemi, pictured here on July 15, was postponed
A scheduled visit to Saudi Arabia by Iraqi Prime Minister Mustafa al-Kadhemi, pictured here on July 15, was postponed POOL / AHMAD AL-RUBAYE

Iraq's oil, finance, electricity and planning ministers arrived in Saudi Arabia on Sunday to begin meetings ahead of Kadhemi's visit, Iraqi officials told AFP.

The delegation was set to return to Baghdad after the meetings wrap up on Monday afternoon.

Under the king's rule, Saudi Arabia has launched ambitious economic reforms for a post-oil era and given more rights to women, but also adopted a more assertive foreign policy
Under the king's rule, Saudi Arabia has launched ambitious economic reforms for a post-oil era and given more rights to women, but also adopted a more assertive foreign policy AFP / AMER HILABI

Kadhemi's trip to Tehran -- Riyadh's arch-rival -- which had been planned to take place immediately after his Saudi visit, was still on, the officials added.

Kadhemi is expected to meet Supreme Leader Ali Khamenei in Tehran on Tuesday.

In a delicate balancing act, Baghdad, often trapped in the tug-of-war between Riyadh, Tehran and Washington, has sought to maintain relations with regional rivals as it also reels from a slump in energy prices.

"I wish @KingSalman a speedy recovery & look forward to seeing him at the earliest possible time, as we'll reschedule my visit soon," Kadhemi wrote on Twitter.

"Iraq's relations with (Saudi) are strong & based on mutual strategic interests & brotherly ties. I'm optimistic about the potential & future of our ties," he added, a view echoed by Adel al-Jubeir, the Saudi minister of state for foreign affairs.

Under the king's rule, Saudi Arabia has launched ambitious economic reforms for a post-oil era and given more rights to women, but also adopted a more assertive foreign policy and entered a war in neighbouring Yemen.

King Salman took the throne after the death of his half-brother Abdullah, who was around 90 years old.

In 2017, Saudi Arabia dismissed reports and mounting speculation that the king was planning to abdicate in favour of his young son, Crown Prince Mohammad bin Salman, who is widely seen as the de facto ruler.

"There is no possibility whatsoever that the king will abdicate," an unnamed Saudi official told Bloomberg News, adding that Saudi kings usually remain in power even when poor health prevents them from carrying out their responsibilities.

Prince Mohammed's meteoric rise has coincided with a sweeping crackdown on critics and dissenters, as well as royal family members.

Saudi Arabia has been engulfed by a series of controversies since he was named crown prince and heir to the throne in June 2017.

That includes the brutal October 2018 murder of royal insider-turned-critic Jamal Khashoggi by Saudi agents at the kingdom's consulate in Istanbul.