Hawzah News Agency - United States President Donald Trump declined to commit to ordering the FBI to investigate the murder of Washington Post columnist Jamal Khashoggi and suggested that Saudi pledges to spend billions of dollars on US military equipment were more important to him because of the impact on the economy.

In an interview broadcast on NBC on Sunday, Trump said Khashoggi's killing has been "heavily investigated".

In a highly-anticipated report into the murder released on Wednesday, the United Nations extrajudicial executions investigator, Agnes Callamard, stated there was "credible evidence" to warrant investigation and financial sanctions against Saudi Arabia's Crown Prince Mohammad bin Salman or MbS as he is commonly known, over Khashoggi's killing in the Saudi consulate in Istanbul last October.

It has been widely reported that the CIA has concluded that MbS ordered an operation to kill Khashoggi. The US Senate has also adopted a resolution naming MbS as "responsible" for the murder. Riyadh has repeatedly denied the involvement of the crown prince. Khashoggi's writings were critical of the Saudi de-facto leader.

"Saudi Arabia is a big buyer of (American) product. That means something to me. It's a big producer of jobs," Trump noted, adding that the subject of Khashoggi "didn't come up" when he and the crown prince spoke last Thursday, largely about Iran.

Khashoggi's remains have not been found but Callamard has announced that she and her team of forensic and legal experts had access to a part of "chilling and gruesome audio materials" of his death obtained by the Turkish intelligence services.

Trump declined last year to punish Saudi Arabia over the killing. Khashoggi had been living in the US at the time of his death.

Trump said he's "not like a fool" that will refuse to do business with the US ally, arguing that the kingdom will turn to US rivals China and Russia if Washington refuses to sell arms to the Saudis.