The United States has placed punishing economic sanctions on 17 Saudis allegedly involved in the murder of journalist Jamal Khashoggi, including top aides of Crown Prince Mohammed bin Salman.

“The Saudi officials we are sanctioning were involved in the abhorrent killing of Jamal Khashoggi. These individuals who targeted and brutally killed a journalist who resided and worked in the United States must face consequences for their actions,” said Treasury Secretary Steven Mnuchin.

The 17 included Saud Al-Qahtani and Maher Mutreb, key aides of the powerful prince, and Mohammed Alotaibi, who was the consul general in the Istanbul consulate when Khashoggi was murdered.

The US Treasury said Qahtani, Prince Mohammed’s long-time right-hand man, “was part of the planning and execution of the operation” to kill Khashoggi.

But it did not point any fingers at Prince Mohammed, who the Saudi government has insisted did not order the killing.

The sanctions, which fall under the US Global Magnitsky Human Rights Accountability Act, freeze any assets those blacklisted have under US jurisdiction, and forbid Americans and US companies from doing business with them.

It came as Saudi Arabia’s top prosecutor recommended the death penalty for five suspects charged with ordering and carrying out the killing of the Saudi writer.

Saud al-Mojeb told journalists in a rare press conference in Riyadh that Khashoggi’s killers had set in motion plans for the killing on September 29, three days before he was killed inside the kingdom’s consulate in Istanbul.

A spokesman for the Saudi public prosecutor’s office said the deputy chief of Saudi intelligence, General Ahmed al-Assiri, had given an order to force Khashoggi home - and “the head of the negotiating team” that flew to Istanbul had ordered his murder.

The prosecutor says 21 people are now in custody, with 11 indicted and referred to trial.

Khashoggi died after being drugged by the five accused and then dismembered, a spokesman for the public prosecutor’s office said in the first Saudi acknowledgment of the manner of his killing.

The journalist’s body parts were then handed over to an agent outside the consulate grounds, the spokesman said.

Khashoggi, 59, was a Washington Post columnist and critic of Crown Prince Mohammed bin Salman.

The announcement appears aimed at distancing the killers and their operation from Crown Prince Mohammed bin Salman, whose decision-making powers are at the centre of global outcry over the killing.

The brutal death of Khashoggi has shocked the world and led many analysts and officials to believe it could not have been carried out without the prince’s knowledge.

Turkey says an assassination squad was sent from Riyadh for the writer and insists the orders for the killing came from the highest levels of the Saudi government, but not King Salman.

But Turkey says that the Saudi prosecutor’s statements on Khashoggi’s killing are “unsatisfactory,” and insists that the suspects be tried in Turkey.

Turkey also says the Saudi investigation needs to reveal who ordered the killing.

Turkish President Recep Tayyip Erdogan has said the order came from “the highest levels” of the Riyadh government, but stopped short of pointing the finger of blame at the Saudi crown prince.

“We find all those steps positive but insufficient,” Foreign Minister Mevlut Cavusoglu said in a televised speech.

Mr Cavusoglu said: “Those who gave the command as well as instigators should also be clarified and this process should not be covered up.”

He said Turkey would continue to do what was necessary “to shed light on this murder in all its aspects.”