United States (US) President Donald Trump on Tuesday denounced the Saudi handling of the death of journalist Jamal Khashoggi, calling it the "worst cover-up ever", as Washington was revoking visas of Saudi officials involved in the case.

He told reporters at the White House the incident was poorly managed by the Saudi authorities, reported Xinhua news agency.

"Somebody really messed up. And they had the worst cover-up ever," he said, describing the killing and following cover-up later in the day, as "a total fiasco."

Trump also revealed that he would be fully informed by the US intelligence personnel who were on their way back after investigations in Turkey and Saudi Arabia.

Also on Tuesday, US Vice-President Mike Pence said in an interview with The Washington Post, which Khashoggi used to work for, that the US would continue to dig up the truth over the death of the 59-year-old journalist.

"Our administration is determined to use all means at our disposal to get to the bottom of it," he said.

Asked by reporters to comment on Turkish President Recep Tayyip Erdogan's speech on the case, Pence said it "flies in the face of earlier assertions that have been made by the Saudi regime."

Erdogan said Tuesday that Khashoggi's murder was planned days in advance. Later in the day, US Secretary of State Mike Pompeo announced that the US was revoking visas of Saudi officials who were suspected of involvement in the journalist's dath.

It was the first concrete step of punishment taken by the Trump administration after the disclosure of Khashoggi's death at a Saudi consulate in Turkey's Istanbul.

The US State Department later told the media that 21 Saudis were under visa penalties.

Khashoggi, journalist and columnist for The Washington Post, went missing since he entered the Saudi consulate in Istanbul on Oct 2.

A joint Turkish-Saudi team completed an investigation into the case on Thursday after searching the residence of the consul-general as well as the Saudi consulate in Istanbul.