Meanwhile, bin Salman talked with world leaders as accusations swirled about the gruesome killing of Khashoggi, who was tortured before he died.
The face-off came after Russian President Vladimir Putin greeted Bin Salman with an apparent "high five". As CBS News and other outlets have reported, the Central Intelligence Agency has concluded that the crown prince ordered the assassination.
According to SPA, the two leaders met at the residence of the Saudi crown prince - known by his initials MBS - in the Argentine capital and discussed bilateral cooperation between the two friendly countries in the various fields.
Tiger Woods, GOLFTV sink exclusive global content partnership
This is such an exciting time for golf and for me, so to be part of the vision to grow the game all around the world is fantastic. The victor gets $1 million - everyone in the field earned at least $2.6 million on the PGA Tour this season.
The two leaders were in Buenos Aires, Argentina, on Friday for the G20 summit and were seen smiling as they approached each other on the meeting's first day. He told reporters he "exchanged pleasantries" with the Saudi leader but nothing more, adding that a meeting "might" happen, per CNN's Jeff Zeleny.
She did not question the authenticity of the transcripts, which included Macron saying to the prince, "You never listen to me", "Because I told you." and "I am a man of my word".
Ivanka Trump: 'No equivalency' between her private email use and Clinton's
The emails were sent as Ms Trump moved into an adviser's position in her father's administration. She was emphatic that "everything has been preserved" and stored in the White House system.
However, the US Senate is less enthusiastic about Saudi relations, voting this week to end support for the Saudi coalition in the war in Yemen.
The prime minister's aides refused to say whether she would ask the crown prince if he was directly involved in the murder of Jamal Khashoggi.
Trump, in an exclamation-heavy statement before the summit, said it did not matter whether Prince Mohammed knew about Khashoggi's death and that Saudi Arabia was important for business and for its hostility to Iran. The White House was said to prevent CIA Director Gina Haspel from attending a closed-door briefing on the killing this week with senators, prompting more criticism.
Donald Trump warns China he won't back down on trade tariffs
Trump thinks his tariffs are paid by exporters, but they are ultimately a tax on United States consumers and shareholders. Later he described what he said was the "bottom line" in the dealings with China.
Before the G20 formally started, Mr Trump joined the Canadian Prime Minister Justin Trudeau and Mexican President Enrique Pena Nieto to sign the deal that will replace NAFTA (the North American Free Trade Agreement).