Khashoggi lived in self-imposed exile in the USA for the past year and wrote editorial columns for The Washington Post that were critical of Saudi Crown Prince Mohammed bin Salman, the kingdom's heir apparent.
"It was a very painful incident for all the Saudis and for all on this planet".
Saudi Arabia said it signed $56 billion of deals at an investment conference this week and expected the United States to remain a key business partner despite a partial boycott of the event over the killing of Saudi journalist Jamal Khashoggi.
He reiterated that Riyadh would bring to justice those responsible for Khashoggi's death, saying they would be prosecuted in the kingdom, a day after Turkey demanded the extradition of 18 Saudis suspected of involvement in his murder.
Foreign Minister Jubeir, speaking at the same conference, said Riyadh's relations with Washington were "ironclad" amid what he called "hysteria in the media" over Khashoggi's killing.
"Failure of any nation to adhere to worldwide norms and the rule of law undermines regional stability at a time when it is needed most", he stressed.
On the sidelines of a Syria summit in Istanbul, the two leaders had a "relaxed exchange", the Elysee palace said, and agreed not to announce their next positions on the issue without first coordinating "at the European level". He lived in self-imposed exile in the United States for almost a year before his death, had written critically of Prince Mohammed's crackdown on dissent.
"With our collective interests in peace and unwavering respect for human rights in mind, the murder of Jamal Khashoggi in a diplomatic facility must concern us all", Mattis said.
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As the wait for further news about the crash continued on Sunday, dozens of fans gathered at the King Power Stadium to lay floral tributes.
Macron also said that if Saudi Arabia is to be sanctioned, "we must do so across the board".
"Whether or not they acted in the name of the state, that remains to be discussed and investigated", she said. "We will continue to explore additional measures to hold those responsible accountable". We will know the truth.
Oman's foreign minister, Yousuf bin Alawi bin Abdullah, told the forum that Muscat was offering ideas to help Israel and the Palestinians to come together but was not acting as mediator.
On Thursday, CIA Director Gina Haspel briefed US President Donald Trump on the latest developments in the investigation after a fact-finding mission to Turkey.
Once an insider in Saudi royal circles, Khashoggi fell out of favour with the monarchy after Mohammed bin Salman was named heir to the throne a year ago.
Erdogan has said that Turkey would reveal more evidence about the killing but was not in any rush to do so, indicating that Turkish authorities will methodically increase pressure on Saudi Arabia even as the kingdom floats conflicting statements in a vain and often clumsy attempt to end the quandary.
Saudi officials have also said he was accidentally killed in a botched security operation to return him to the kingdom.
Sunni Muslim Saudi Arabia and Shi'ite Muslim Iran, which was not represented in the Manama conference agenda, have always been locked in a proxy war, competing for regional supremacy from Iraq to Syria and Lebanon to Yemen.