US president’s remarks come as Washington says it has identified Saudis responsible for killing and plans punishments.

US President Donald Trump has criticised Saudi Arabia’s handling of the killing of journalist Jamal Khashoggi, saying authorities staged the “worst cover-up ever”.

Asked by a reporter in the White House how the Khashoggi killing could have happened, Trump said on Tuesday: “They had a very bad original concept. It was carried out poorly, and the cover-up was one of the worst in the history of cover-ups.

“There should have never been an execution or a cover-up, because it should have never happened. I would say it was a total fiasco from day one.”

Khashoggi’s death in the Saudi consulate in Istanbul on October 2 has caused global outrage.

Khashoggi, a critic of Saudi Crown Prince Mohammed bin Salman, was a US resident and columnist for The Washington Post.

Trump’s comments about the incident in recent days have ranged from threatening Saudi Arabia with “very severe” consequences and mentioning possible economic sanctions, to more conciliatory remarks highlighting the country’s role as a US ally against Iran, as well as a major purchaser of US arms.

Meanwhile, US Secretary of State Mike Pompeo told reporters on Tuesday that Washington has identified some of the individuals responsible for Khashoggi’s killing and is planning punishments.

“We are taking appropriate actions,” Pompeo said on Tuesday, saying this including possible visa revocations and applying individual sanctions under human rights laws. He noted some of those identified work for ministries and the royal court.

“These penalties will not be the last word on the matter,” he said.

Turkey demands answers

Riyadh initially denied knowledge of Khashoggi’s fate before saying he was killed in a fight in the consulate, a reaction that met scepticism from governments and commentators around the world.

Turkish President Recep Tayyip Erdogan has contradicted that account, saying Khashoggi’s killing was a “political murder” that was planned by Saudi officials days in advance.

He pledged to answer all questions about the death, and stopped short of accusing Saudi royals of the “savage” killing.

Responding to Erdogan’s comments, Trump said the Turkish leader was “pretty rough” on the Saudis and that he wants to get all facts on Khashoggi’s killing before agreeing with that assessment.

Trump, who sent his CIA director to Turkey to discuss the issue, said he expected to have a report soon.

He added that he would defer to the US Congress on a response to Saudi Arabia.

“In terms of what we ultimately do, I’m going to leave it very much – in conjunction with me – I’m going to leave it up to Congress,” Trump said.