A man appearing to wear journalist Jamal Khashoggi's clothes left the Saudi Consulate in Istanbul following his killing there, according to a surveillance video, while a member of Crown Prince Mohammed bin Salman's entourage made four calls to the royal's office around the same time, reports said on Monday.

The reports by CNN and a pro-government Turkish newspaper came just a day before Prince Mohammed's high-profile investment summit is to begin in Riyadh and Turkish President Recep Tayyip Erdogan has promised that details of Khashoggi's killing "will be revealed in all its nakedness".

Th reports add to the pressure Saudi Arabia faces over the slaying of The Washington Post columnist.

The kingdom's claim on Saturday that Khashoggi died in a "fistfight" were met with international scepticism and allegations of a cover-up to absolve the 33-year-old crown prince of direct responsibility.

Turkish media reports and officials maintain that a 15-member Saudi team flew to Istanbul on Oct 2, knowing Khashoggi would arrive for a document he needed to get married.

Once he was inside the diplomatic mission, the Saudis accosted Khashoggi, cut off his fingers, killed and dismembered the 59-year-old writer.

CNN aired surveillance footage on Monday showing a man in Khashoggi's dress shirt, suit jacket and pants.

It cited a Turkish official as describing the man as a "body double" and a member of the Saudi team sent to Istanbul to target the writer.

The man is seen in the footage walking out of the consulate via its back exit with an accomplice, then taking a taxi to Istanbul's famed Sultanahmet Mosque, where he went into a public bathroom, changed back out of the clothes and left.

The state-run broadcaster TRT later also reported that a man who entered the consulate building was seen leaving the building in Khashoggi's clothes.

In the days after Khashoggi vanished, Saudi officials initially claimed that he had left the consulate, implying premeditation on the part of the Saudi team.

"After Turkish authorities and the media were allowed to inspect the consulate building in its entirety, the accusations changed to the outrageous claim that he was murdered, in the consulate, during business hours, and with dozens of staff and visitors in the building," Saudi Ambassador to the US Prince Khalid bin Salman, a brother of the crown prince, wrote on Oct 8.

"I don't know who is behind these claims, or their intentions, nor do I care frankly."

A separate report by newspaper Yeni Safak said that Maher Abdulaziz Mutreb, a member of Prince Mohammed's entourage on trips to the United States, France and Spain this year, made the calls from the consulate.

The newspaper said the four calls went to Bader al-Asaker, the head of Prince Mohammed's office.

It said another call went to the United States.

Yeni Safak cited no source for the information. However, pro-government newspapers have been leaking information about Khashoggi's killing, apparently with the help of Turkish security forces.

Yeni Safak reported last week that Saudi officials cut off Khashoggi's fingers and then decapitated him at the consulate as his fiance waited outside.

Officials in Saudi Arabia have not answered repeated requests for comment from The Associated Press in recent days, including on Monday.

Saudi Arabia so far has not acknowledged or explained Mutreb's presence in Istanbul, nor that a forensics and autopsy expert was also on hand for Khashoggi's arrival at the consulate.

Last week, a leaked photograph apparently taken from surveillance footage showed Mutreb at the consulate, just ahead of Khashoggi's arrival.

Mutreb's name also matches that of a first secretary who once served as a diplomat at the Saudi Embassy in London, according to a 2007 list compiled by the British Foreign Office.

Meanwhile, Saudi state media reported that both Prince Mohammed and King Salman made calls to Khashoggi's son, Salah, early on Monday morning.

Statements from the agency said both the king and the crown prince expressed their condolences for Khashoggi's death.

A Saudi friend of Khashoggi who was in frequent touch with him before his death told the AP that Salah Khashoggi had been under a travel ban and barred from leaving the kingdom since last year as a result of his father's criticism of the government.

The friend spoke on condition of anonymity for fear of repercussion.

The Saudi statements did not acknowledge the ban.

Five Turkish employees of the consulate also gave testimonies to prosecutors on Monday, Turkish media reported.

Istanbul's chief prosecutor had summoned 28 more staff members of the Saudi Consulate, including Turkish citizens and foreign nationals, to give testimony.

Some Turkish employees reportedly said they were instructed not to go to work around the time that Khashoggi disappeared.

Saudi Foreign Minister Adel al-Jubeir on Sunday told Fox News that Khashoggi's killing was "a rogue operation" and that "we don't know where the body is".

"The individuals who did this did this outside the scope of their authority," he said. "There obviously was a tremendous mistake made and what compounded the mistake was the attempt to try to cover up. That is unacceptable to the government."

However, leading Republicans and Democrats in Congress are saying Saudi Arabia should face punishment over Khashoggi's killing.

US President Donald Trump also had talked about possible punishment but said he didn't want to halt proposed arms sales to Saudi Arabia because he maintained it would harm American manufacturers.

Britain, Germany and France issued a joint statement condemning the killing of Khashoggi, saying there is an "urgent need for clarification of exactly what happened".

In a statement on Sunday, the governments said attacks on journalists are unacceptable and "of utmost concern to our three nations".

They said the "hypotheses" proposed so far in the Saudi investigation need to be backed by facts to be considered credible.

German Chancellor Angela Merkel told reporters in Berlin on Sunday that she supports a freeze on arms exports to Saudi Arabia.

German Economy Minister Peter Altmaier underlined that point on Monday, calling for a joint European position as Germany "won't at this point approve any further arms exports because we want to know what happened".

Saudi says no plans for embargo despite Khashoggi row

Saudi Arabia today said that it had no plans to repeat its harsh 1973 oil embargo, even as relations with the West sour following the killing of Khashoggi.

Riyadh, long the world's biggest oil producer, hiked prices sharply during the 1973 Yom Kippur War, setting off a wave of inflation that plunged developed economies into years of crisis.

Saudi Oil Minister Khaled al-Faleh told the TASS news agency that "there is no intention" of repeating the events of 1973.

"Saudi Arabia is a completely responsible country. For decades, we have used our oil (production) policy as a responsible economic tool and we have kept it apart from politics," Faleh was quoted as telling TASS in an interview in Riyadh.

"If oil prices were to rise too much, that would slow the global economy and set off a global recession."

"Saudi Arabia has been coherent in its policy. We work to stabilise global markets and to facilitate global economic growth," he added.

Riyadh's changing accounts of what happened to Khashoggi, an insider turned critic of the government, have run into increasing western scepticism, with even firm ally US President Donald Trump saying the government had lied about what happened.

In its latest version, the government conceded that Khashoggi was killed by mistake in its Istanbul consulate but this only sparked more calls for a complete and transparent investigation, coupled with the threat of sanctions.

"This incident will pass," al-Faleh forecast.