Khashoggi was a Washington Post columnist living in Virginia who was critical of the Saudi government before he disappeared at the country's consulate in Istanbul on October 2.
Turkey has said the murder was carried out by a team of Saudis who travelled to Istanbul for that objective.
While the Trump administration on Thursday imposed sanctions on 17 Saudis for their role in Khashoggi's killing, many lawmakers think the United States should take a tougher stance, and the CIA's findings are likely to embolden that view.
The Post, citing unnamed sources, also reported that USA intelligence agencies reviewed a phone call that the prince's brother, Khalid bin Salman, had with Khashoggi.
Trump said he "was fully briefed on it, there's no reason for me to hear it". The United States continues to diligently work to ascertain all of the facts and will hold accountable each of those we find responsible in order to achieve justice for Khashoggi's fiancée, children, and the family he leaves behind.
Saudi Arabia is a major oil supplier and a close ally of the United States in countering Iranian power in the Middle East. Canada, which went through its own dispute with the Gulf state earlier this year over its human rights record, cheered the White House's move.
Shalaan al-Shaalan, the kingdom's deputy public prosecutor, revealed that 21 people are in custody over the grisly killing and charges have been brought against 11 of them.
"I have to take a lot of things into consideration" when deciding what measures to take against the kingdom, he said.More news: Dr. Miriam Adelson one of seven to receive Presidential Medal of Freedom
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Trump and top officials of his administration have said Saudi Arabia must be held to account for any involvement in Khashoggi's death, but they have also stressed the importance of the U.S. -Saudi alliance.
Trump has called the killing a botched operation that was carried out very poorly and has said "the coverup was one of the worst coverups in the history of coverups".
But he has resisted calls to cut off arms sales to the kingdom and has been reluctant to antagonise the Saudi rulers.
This past week, US intelligence officials briefed members of the Senate and House intelligence committees, and the Treasury Department announced economic sanctions on 17 Saudi officials suspected of being responsible for or complicit in the killing.
Mr Trump considers the Saudis vital allies in his Mideast agenda.
Vice President Mike Pence told reporters travelling with him on Saturday for a summit of Pacific Rim nations in Papua, New Guinea, that the "murder of Jamal Khashoggi was an atrocity".
Trump said on Saturday that the Central Intelligence Agency assessment was "very premature" and in the interview that aired on Sunday he said it may never be possible to know who ordered Khashoggi's murder. "America's response to Khashoggi's murder has significant implications for our credibility around the globe, and there must be further sanctions on Saudi leadership who ordered this assassination".
The suspects had allegedly set in motion plans for Khashoggi's murder on September 29, three days before he was last seen entering the Saudi Arabian consulate in Istanbul, al-Mojeb said during a televised press conference in Riyadh.