Trump has also insisted that killing will not interfere with U.S. arms sales to Saudi Arabia, citing a $110bn deal with Riyadh he announced past year.
Turkey has continued to demand more answers from Saudi Arabia.
The photos of him meeting with the king and the crown prince were released by the Saudi government in an apparent effort to showcase their sympathy.
Saudi Arabia's King Salman spoke with Russian president Vladimir Putin by telephone on Thursday to brief him on the investigation into the murder of Saudi journalist Jamal Khashoggi, according to the official Saudi press agency.
Global leaders and groups continue to call on the Saudi government to be truthful about what happened to Khashoggi.
On Thursday, a Saudi public prosecutor said the killing was premeditated, citing the Turkish-Saudi joint probe, Saudi media said.
Asked by a reporter in the White House how the Khashoggi killing could have happened, Trump said: "They had a very bad original concept".More news: Sarri: Manchester United are the best in the Premier League
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How world leaders treat Riyadh going forward appears to hinge on the extent to which they believe the Saudi version of events and how much responsibility sits with the country's powerful crown prince, Mohammed bin Salman.
Turkish officials and some US lawmakers allege the crown prince ordered the operation in which Jamal Khashoggi killed.
Shortly after Khashoggi disappeared on October 2 while retrieving a document at the Saudi Consulate in Istanbul, Turkish authorities said he was the victim of a premeditated killing by 15 Saudi agents sent to Turkey on a mission to permanently silence the journalist, who had been critical of Saudi Crown Prince Mohammed bin Salman.
Mevlut Cavusoglu is Turkey's foreign minister.
Also Thursday, the European Union issued a fresh condemnation of Khashoggi's killing and reiterated its skepticism that it could have been carried out without Mohammed's knowledge.
"But we have enough right now to determine that the government of Saudi Arabia is responsible and is implicated".
"What we know is sufficient to suggest very strongly that Mr Khashoggi was the victim of an extrajudicial execution", Agnes Callamard told Al Jazeera. The Turks have identified a Saudi forensics specialist who is an expert in mobile autopsies and who had traveled to Istanbul the day Khashoggi was planning to visit the consulate.
After the journalist disappeared, Saudi Arabia initially insisted Khashoggi had walked out of the consulate after visiting the building.