When Jordan’s military chief approached Prince Hamzah at his home in Amman, he displayed the respect due to a former crown prince in the Hashemite dynasty. But his message rang as a threat: he must stop associating with palace critics.

“Sir, this talk, you and I know, breaches the red lines,” said Major General Yousef Huneiti. “People are talking more than is necessary. Therefore, we hope from His Highness that starting from this day, you . . . will comply to not go to these occasions, not mixing with people.”

The request prompted an angry reaction from the 41-year-old royal, once in line to be king.

“You come here and you’re telling me what to do and who to meet from my people,” Hamzah is heard shouting in a recording obtained by the Financial Times. “The mismanagement of the state, is it because of me? The failure that is happening, is it because of me?”

Saturday’s exchange — recorded by the prince and disseminated by his allies — marked the beginning of 48 hours of palace turmoil in one of the Arab world’s most respected royal families. It was a drama replete with Shakespearean twists that has unfolded in full public glare.

Hours later, Huneiti issued a statement saying he had warned the prince to stop activities that threatened the stability and security of the nation. Hamzah then claimed in a video posted on social media that he was under house arrest, and launched a tirade against corruption and nepotism within the ruling elite.

A day later, the authorities accused him of being part of a conspiracy to destabilise the kingdom involving foreign as well as domestic parties, sending shockwaves across the region.

Up to 18 people were arrested, mostly friends and acquaintances of the prince. A Jordanian government official said the move against Hamzah and his entourage came after King Abdullah was told by the heads of security agencies that his half-brother had shifted from criticism of the king to action against him. Suspicious behaviour included paying visits to 60 tribal leaders — the bedrock of the Hashemite monarchy.

Among those detained was Bassem Awadallah, once chief of staff to King Abdullah and now a close adviser to Saudi Arabia’s crown prince Mohammed bin Salman.

Though he has often been described as King Abdullah’s envoy to Saudi Arabia, Awadallah — who is believed to have both Jordanian and Saudi citizenships — is distrusted by the Jordanian palace. He coached and advised Hamzah, one palace official claimed. According to a person familiar with contacts between Saudi and Jordanian officials, Riyadh asked that Awadallah be handed over, a request the Hashemite kingdom rejected. A person briefed on the Saudi position denied such a request had been issued.

Some analysts, however, questioned the link between Hamzah and Awadallah.

“Hamzah is a smart guy, he knows Awadallah is unpopular in Jordan, and the prince has been going around the country, speaking out against corruption and the new liberal recipe of the economy championed by Awadallah [in the 1990s and 2000s],” said Hassan Barari, a Jordanian professor of international relations at Qatar University. “If he had any ambition, he would have been stupid to have any links with him.”

Barari added: “The regime made a mistake involving Prince Hamzah. He’s popular among Jordanians.”

Though there is no talk of a coup — the army is firmly in the hands of the king — the intercepted communication following the meetings with tribal leaders and mounting domestic pressures exacerbated by the coronavirus pandemic has raised alarm among security agencies and the palace.

Family tree for the Jordan royal family

Hamzah’s supporters portray him as the victim of King Abdullah’s increasing intolerance of dissenting voices. But people close to the palace describe a man obsessed with the throne, who has been exploiting the country’s economic woes to undermine his brother.

“He never got over the fact that he didn’t become king and seems to think he is destined to be king,” said a person close to the palace.

A person close to Hamzah insisted the prince was not campaigning: “His fear has always been one of fear for his whole family and its legacy. He would never do anything to jeopardise his family for his own position.”

The sibling feud has been years in the making. People familiar with palace politics say Hamzah was King Hussein’s favourite son — he speaks, dresses and looks like his late father — and Queen Noor, his American-born mother, had been grooming him since he was a child.

At the weekend the 69-year-old queen, the late king’s fourth wife, wrote on Twitter that she was praying for the “innocent victims of this wicked slander”.

Two weeks before Hussein’s death in 1999, Abdullah, who is 18 years older than Hamzah, was named crown prince and heir apparent. The anointing of Abdullah, son of the king’s British-born second wife Princess Muna, pushed aside Abdullah’s uncle Hassan in another episode of palace intrigue. The ailing monarch reportedly decreed that after his death Hamzah should be crown prince — an arrangement that fuelled speculation about a potential power struggle. In 2004, King Abdullah removed Hamzah as crown prince, paving the way for his own son, Hussein, to succeed him.

A person close to Hamzah described the relationship between the royal brothers as “very antagonistic”. It began “with grumbling acceptance” of Abdullah’s decision to sideline his younger brother, but it “snowballed” as Hamzah believed people around the monarch were corrupt and “stealing everything”.

“It is known that Hamzah and Abdullah don’t speak,” the person said. The former was fired from the army several years ago and measures were taken to irritate him, including changes to his security detail so he felt it was “not protecting him, but spying on him”, the person claimed.

Those close to Abdullah say the king’s patience has run out. When anti-government protests erupted in 2018, causing the king to sack his prime minister, the prince took to Twitter to demand a crackdown on corruption in the public sector, they noted.

“The king has been magnanimous,” said one person close to the palace. “But Hamzah pushed it. He trashed the state and moved with the protection of the state. He has been using his privileges as a prince to work against the king.”

A deteriorating economy has heaped pressure on the king. Jordan is grappling with rampant unemployment, soaring debt and dwindling revenues. The pandemic has hurt tourism and flows of remittances from abroad, two important sources of foreign currency. Rich Gulf states have become more frugal in providing financial support to the kingdom. The Trump presidency strained Abdullah’s relationship with Saudi Arabia’s crown prince and Benjamin Netanyahu, Israel’s prime minister.

The royal family is now seeking to paper over the cracks. On Monday, the royal court said that after meeting senior family members Hamzah signed a letter pledging his loyalty to the king. It was Prince Hassan, the uncle sidelined years ago by the late Hussein to give way to Abdullah, who acted as an intermediary.

On Tuesday, the palace banned news outlets and social media users from publishing content related to the dispute, including the audio file of the Saturday exchange with Huneiti.

“It's probably not the end of the story,” said one person close to the royal family.

Additional reporting by Heba Saleh in Cairo