Turkish authorities say a team of Saudis killed Khashoggi, and US intelligence intercepts show Saudi officials discussing an operation to lure Khashoggi - a Saudi citizen who had been living in the US - back to Saudi Arabia from his home in Virginia and detain him.
Speaking with reporters at the White House later, Trump reiterated that there would be "very powerful" repercussions for Saudi Arabia should the US determine that the kingdom is responsible for the death of Khashoggi, who wrote for the Post's Global Opinions section.
But the President all but ruled out cancelling US$110 billion in US arms sales to Saudi Arabia, arguing that doing so would be "very foolish for our country" and only end up harming US defence industries and others.
Trump said the United States competed against China, Russia and other countries for the Saudi contracts and winning it was "a tremendous order for our companies".
"I actually think we'd be punishing ourselves if we did that," Trump told reporters, referring to cancelling the arms deal. "There are other things we could do that are very, very powerful, very strong, and we'll do that."
Trump declined to provide an example of an action he was considering taking to punish Saudi Arabia, saying only that "there are many things we could do".
Trump made his comments during an Oval Office meeting with evangelical Christian pastor Andrew Brunson, who returned from Turkey where he had been jailed for nearly two years.
Trump said he plans to review recordings from the Turkish Government that purport to show evidence of Khashoggi's killing.
Asked whether he had reviewed the audio or video recordings, Trump said he has not.
"We've all heard a lot about the audio," Trump said. "Nobody's seen it yet. We do want to see it."
The President confirmed that he had asked the Turkish Government to share the recordings and added, "We're going to be seeing it very soon."
Trump said he would be calling King Salman of Saudi Arabia to discuss the Khashoggi matter.
Trump said that he had invited Khashoggi's fiancee, Hatice Cengiz, to visit him at the White House and that his staff was working out arrangements with her. The President said that Cengiz wrote "a beautiful letter" to him and first lady Melania Trump and that they would welcome her.
"It's looking like he perhaps won't be or isn't around and that's very sad," Trump said of Khashoggi. "I think we would've known by now. Our first hope was that he was not killed, but maybe that's not looking too good."
The Saudi Government issued a statement condemning and denouncing "the false accusations circulated in media reports on the Saudi Government and other people in the purported relation to the disappearance" of Khashoggi.
Saudi Interior Minister, Prince Abdulaziz bin Saud bin Naif bin Abdulaziz, "stressed that what has been circulating in terms of supposed orders to kill Jamal are outright lies and baseless allegations against the Kingdom's Government, which is committed to its principles, rules and traditions and is in compliance with international laws and conventions".
The statement offered no new details. But the careful wording appeared to leave open the possibility that Khashoggi died or was killed during an attempt to detain him, as some have speculated.
Trump campaigned in Richmond, Kentucky, yesterday on behalf of a Republican Midterm election candidate. He plans a swing through Montana, Arizona and Nevada this week.
- Additional reproting AP