US president Donald Trump has dismissed a United Nations request for the FBI to investigate the murder of the dissident journalist Jamal Khashoggi, suggesting it would jeopardise US weapons sales to Saudi Arabia.

A report on Khashoggi’s assassination published last week by the UN special rapporteur on extrajudicial killings said the US should open an FBI inquiry and “pursue criminal prosecutions within the United States, as appropriate”.

However, Mr Trump brushed the proposal aside in an interview broadcast by NBC’s Meet the Press on Sunday.

Asked if he would allow the FBI to investigate, Mr Trump said: “I think it’s been heavily investigated.”

Asked who had investigated, the president replied: “By everybody. I mean… I’ve seen so many different reports.”

Khashoggi (59) was killed when he entered the Saudi consulate in Istanbul, Turkey, in October last year. The UN special rapporteur blamed the Saudi government for the murder, and said there was credible evidence that Crown Prince Mohammed bin Salman and other senior officials were responsible.

Mr Trump told NBC the murder “really didn’t come up” in a call with the prince on Friday.

Mr Trump also suggested Saudi Arabia was no worse than other states in the Middle East, which he called a “vicious, hostile place”, adding: “Look at Iran, look at other countries, I won’t mention names.”

The president then cited a drastically overinflated figure for Saudi spending on US weapons that fact-checkers have previously noted does not match the official record.

“I only say they spend $400 billion to $450 billion over a period of time, all money, all jobs, buying equipment,” Mr Trump said.

In fact Saudi Arabia last year signed “letters of offer and acceptance” for $14.5 billion in military purchases from the US.

Selling arms

The US senate last week voted to block the Trump administration selling arms to Saudi Arabia, with seven Republicans joining Democrats to pass the measure. Mr Trump has pledged to use his presidential veto and push on with the sales.

While denying he was saying such purchases were “the price” for Khashoggi’s murder, Mr Trump on Sunday defended his consideration of arms sales in responding to the assassination. Khashoggi was a US resident who wrote for the Washington Post.

“I’m not like a fool that says, ‘we don’t want to do business with them’.” Mr Trump said. “And, by the way, if they don’t do business with us, you know what they do? They’ll do business with the Russians or with the Chinese…We make the best equipment in the world but they will buy great equipment from Russia and from China. ”