"I spoke directly to the crown prince to highlight our concerns and our need for better answers on the killing of Khashoggi", Trudeau said.
Pompeo also said in the interview that the U.S. will continue to provide military support to the kingdom in the war in Yemen.
Salman, who has been accused by the worldwide community of ordering the killing of journalist Jamal Khashoggi, and Putin, who has faced claims he ordered the nerve attack on Sergei Skripal in Britain, were pictured hand-in-hand during the second day in Buenos Aires.
He pointed out that the US-Saudi relationship "has mattered" for 70 years across Republican and Democrat administrations alike.
Canada has been outspoken on human rights in Saudi Arabia, which has retaliated by breaking off diplomatic relations and vowing to end trade.
Trudeau stressed that he continues to believe "frank and direct" conversations with leaders matter, adding they are what Canadians expect him to do and what the world has come to expect of Canada.
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Those who were arrested were accused of illegally entering the US ; 27 were men and 15 women and children. They briefly escaped and were captured.
The Journal also reported on Friday that in August 2017, MBS had told associates if his efforts to persuade Khashoggi to return to Saudi Arabia were unsuccessful, "we could possibly lure him outside Saudi Arabia and make arrangements".
Saudi Crown Prince Mohammed bin Salman sent at least 11 messages to the adviser who oversaw the effort to kill Jamal Khashoggi in the hours around the journalist's killing, according to a classified Central Intelligence Agency report obtained by The Wall Street Journal.
Turkey's Erdogan has said Jamal Khashoggi's murder was ordered by the highest level of Saudi leadership. "But his own officials have admitted that this was a planned operation".
President Donald Trump, who also has been briefed on the CIA's findings, has been equivocal in assigning blame to the crown prince, who works closely with the president's son-in-law and senior adviser Jared Kushner on Middle East issues.
The president has said that the strategic relationship with Saudi Arabia and the benefit to the USA economy from Saudi arms purchases are too important to rupture over the killing of Khashoggi, which he has condemned.
The US Treasury Department has sanctioned 17 individuals it said were involved in Khashoggi's death, including Qahtani, Mutreb and the Saudi consul general in Turkey, Mohammad al-Otaibi.
Last week, in a rebuke of Saudi Arabia and the administration's handling of the Khashoggi case, a majority of the Senate voted to advance a measure to end U.S. military support to Saudi Arabia for its war in Yemen against Iranian-backed militants.