The CIA says Saudi Crown Prince Mohammed bin Salman ordered the assassination of Jamal Khashoggi, according to a US official.
Officials had high confidence in the CIA's findings, which link the prince to the killing of the journalist and prominent critic of the Saudi regime, according to the Washington Post.
Riyadh's ambassador to US – and brother of the kingdom's de facto leader – Prince Khalid bin Salman swiftly denied claims in the newspaper that he had spoken with Mr Khashoggi on the phone or that he suggested he go to Turkey "for any reason".
"I ask the US government to release any information regarding this claim," he wrote on Twitter.
It comes as Saudi prosecutors sought the death penalty for five suspects charged with the murder of Mr Khashoggi.
The kingdom's public prosecutor Saud al Mojeb said in a statement that 21 people were now in custody over the killing, with 11 people indicted and facing trial.
The highest-level official accused of being behind the murder is former deputy intelligence chief Ahmad al Assiri, according to the prosecutor's spokesman Shaalan al Shaalan.
He said the Washington Post columnist's alleged killers had set in motion plans for the murder on 29 September, three days before he died inside the kingdom's consulate in Istanbul.
The public prosecutor's office appeared to distance the alleged killers and their operation from the Saudi prince and accused two senior officials of giving the orders.
Mr al Shaalan denied the Saudi prince had any knowledge of the killing in response to a journalist's question.
Earlier on Friday, Turkish President Recep Tayyip Erdogan and Donald Trump spoke on the phone and agreed on the need to prevent any cover-up of the killing, according to a source close to the Turkish leader.
Turkish media also claimed authorities had further evidence to discredit Riyadh's version of events, including a second audio tape.
Mr al Shaalan to reporters Mr Khashoggi was killed on 2 October after he was given a lethal injection, before his body was dismembered and taken out of the building.
He said the writer was murdered after "negotiations" for his return to the kingdom failed and that the person who ordered the killing was in fact the head of the negotiating team.
He said the whereabouts of Mr Khashoggi's body remained unknown.
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On Friday, hundreds of people attended a symbolic funeral in Istanbul for the columnist as his loved ones came to terms with the prospect of never finding his body.