ISTANBUL — President Recep Tayyip Erdogan of Turkey swept into Ankara’s wood-paneled Parliament on Tuesday to level his most direct attack yet against Crown Prince Mohammed bin Salman of Saudi Arabia, accusing his government of planning the “savage murder” and mutilation of the dissident writer Jamal Khashoggi.
Hours later, Prince Mohammed bounded into the gilded conference hall of the Ritz-Carlton Hotel in Riyadh to a standing ovation from scores of oil executives, bankers and other businessmen who had risked association with scandal over the killing of Mr. Khashoggi for a chance to profit from the kingdom’s vast wealth.
“More people, more money,” the crown prince told reporters, pronouncing the event a success despite the withdrawal of dozens of speakers and the pleas of many businessmen for him to spare them embarrassment by calling it off.
Their competing stage shows on Tuesday were the latest salvos in an increasingly high-stakes battle that no longer appears to leave either one room for retreat, pitting against each other two American allies who have each aspired to be the leader of their region.
In Washington, President Trump made his strongest criticism yet of his Saudi ally. He pronounced the latest official Saudi account of Mr. Khashoggi’s disappearance — that he was strangled to death by accident during an attempt to persuade him to come home — “the worst cover up ever.” He had deemed it “credible” just a few days before.
In its first punitive response in the three weeks since the disappearance, the administration also said it would revoke the visas of 21 Saudis suspected of killing Mr. Khashoggi, a Virginia resident and Washington Post columnist.
Mr. Erdogan, with his speech on Tuesday, has now committed himself to exploiting the international uproar over the killing to inflict as much damage as possible on the public image of the crown prince, who had marketed himself to the West as a bold reformer and pivotal ally. At the same time, Mr. Erdogan continued to hold in reserve his biggest gun: the release of an audio recording and other evidence Turkish officials claim to have of the assassination.
With his own display of political muscle at the investor conference, Prince Mohammed flaunted his refusal to pull back in the face of the scandal, demonstrating that the lure of kingdom’s vast oil deposits and sovereign wealth fund could still compel executives to pay tribute despite the backlash.
It hardly seemed to matter that there were empty rows of gilded chairs at the afternoon sessions. The Saudi royal court said it would announce $50 billion worth of deals from the conference, with companies from Hyundai to Halliburton.
And in a pointed message to Washington, the Saudi media lavished special attention on a Russian fund manager close to President Vladimir Putin.
“Saudi Arabia is a great partner for us,” the fund manager, Kirill Dmitriev, proclaimed.
It was a tacit reminder to the world that, at 33 years old, the crown prince could remain among the powerful figures in the Middle East for decades no matter what evidence Turkey produces.
As if to drive that home, he stopped in front of video cameras at a palace in Riyadh to express condolences over a carefully staged handshake with Mr. Khashoggi’s son, Salah.
Salah Khashoggi, who has been barred from leaving the kingdom, looked pained. His father was a well-known critic of the crown prince and a growing number of current and former Western officials with experience in the kingdom have said that the crown prince almost certainly authorized the killing.
His son appeared to have little choice about the handshake, which was broadcast over Saudi-owned media.
The crown prince “has definitely established a climate of fear inside the kingdom, and the Khashoggi killing has only reinforced that,” said Bruce Riedel, a former American intelligence official specializing in Saudi Arabia.
The investor conference took place in the same hotel that the prince used last year as a prison to detain about 200 businessmen and royals while he squeezed them to turn over billions of dollars he claimed had been obtained through unspecified corruption.
But if the crown prince’s power appears unchallenged inside the kingdom, Mr. Erdogan also made clear Tuesday that he has no intention of backing off what appears to be an escalating campaign to discredit the crown prince in the eyes of much of the rest of the world.
In his first public statements detailing the accusations about Mr. Khashoggi’s killing, Mr. Erdogan charged Tuesday that as soon as the diplomats in the consulate knew Mr. Khashoggi would be coming back for a document, one flew back to Riyadh, where “a road map started to be established.” Then a team of 15 Saudi agents had flown to Istanbul on Oct. 2 for an ambush.
“It is clear that this savage murder did not happen instantly but was planned,” Mr. Erdogan said, directly challenging the Saudi account and demanding punishment “to the highest levels.”
Other Turkish officials, speaking on condition of anonymity, have already let out more lurid details said to come from confidential intelligence: that within minutes of Mr. Khashoggi’s arrival in the consulate the team had killed and dismembered him. Reports that the team included a top Saudi doctor specializing in autopsies who brought a bone saw to the consulate have given the crown prince, often known as M.B.S., a new nickname — Mr. Bone Saw.
“The Saudis are under pressure that they can’t buy their way out of this time,” said Aaron David Miller, a former state department official and scholar at the Wilson Center. “Neither their oil nor their money are going to be able to erase the stain, or silence the glee of their enemies, including Erdogan.”
Mr. Erdogan’s speech on Tuesday seemed mainly aimed at an audience of two: King Salman, the crown prince’s aging father, and President Trump.
Mr. Erdogan at least twice singled out King Salman for praise and deference.
“I do not doubt the sincerity of King Salman,” he said.
The king is the only one in Saudi Arabia who might curb the power of the crown prince without an act of violence, and Mr. Erdogan appeared to seek to divide them.
Without mentioning Prince Mohammed by name, Mr. Erdogan “distinguished between King Salman and all the other suspect people in Saudi Arabia,” said Yasin Aktay, an adviser to President Erdogan and a senior official of his ruling Justice and Development party. “He said he is asking for and he expects the king to address the demands for justice.”
He also respectfully cited a recent phone call with President Trump.
“We have agreed to bring light to every aspect of this issue,” Mr. Erdogan said.
Two people close to Mr. Erdogan, speaking on condition of anonymity to discuss conversations with the president, said he believes persuading Mr. Trump to abandon Prince Mohammed would be a prerequisite to any attempt to constrain or remove him.
Turkish officials have been feeding graphic leaks to the news media about Mr. Khashoggi’s killing in part to try to turn American public opinion and thus Mr. Trump against Prince Mohammed.
Yet turning the White House against the prince appears unlikely, in part because the president’s son-in-law and Middle East adviser Jared Kushner has invested deeply in Prince Mohammed as a pillar of the administration’s strategies to both contain Iran and secure Israel.
Prince Mohammed had grinned through a photo session on Monday with Treasury Secretary Steven Mnuchin, and his visit appeared to convey the continued support of the White House, Mr. Trump’s subsequent comments notwithstanding.
Mr. Erdogan understands this, the two people close to him said. But he has evidently calculated that the chance to weaken Prince Mohammed by tarring him with the Khashoggi killing is worth the risk of facing him as a hostile of ruler of Saudi Arabia for the next 50 years.