Saudi Foreign Minister Adel al-Jubeir insisted on Sunday that the kingdom did not know where the body of slain journalist Jamal Khashoggi was, AFP reported.

Speaking in an interview on Fox News, Jubeir said the Saudi leadership initially believed Khashoggi had left its diplomatic mission in Istanbul, where he was last seen on October 2.

But following "reports we were getting from Turkey," Saudi authorities began an investigation, which discovered "he was killed in the consulate", added Jubeir.

"We don't know, in terms of details, how. We don't know where the body is," the Saudi minister insisted, adding that the Saudi public prosecutor had ordered the detention of 18 individuals, "the first step in a long journey."

He termed the killing a "tremendous mistake" but one which the US-Saudi relationship would eventually overcome.

"The individuals who did this, did this outside the scope of their authority. There obviously was a tremendous mistake made, and what compounded the mistake was the attempt to try to cover up," Jubeir said.

"That is unacceptable in any government. These things unfortunately happen. We want to make sure that those who are responsible are punished, and we want to make sure we have procedures in place to prevent it from happening again," he stressed.

Saudi Arabia admitted for the first time on Friday that Khashoggi was killed after entering the consulate in Istanbul.

A report on Saudi Arabia's state-owned television channel said that Khashoggi was murdered at the consulate earlier this month after a brawl broke out. According to the report, the meeting "did not go as required and developed in a negative way, leading to a fight and a quarrel".

"The brawl aggravated to lead to his death and their attempt to conceal and cover what happened".

Turkish officials concluded two weeks ago that Khashoggi, a prominent Saudi journalist who was also a contributor to The Washington Post, was murdered inside the Saudi mission in Istanbul after going missing.

Until Friday, Saudi Arabia denied the Turkish claims, saying it had no knowledge of his whereabouts and insisting he left the building alive.

On Saturday, US President Donald Trump made clear that he is "not satisfied" with Saudi Arabia's account of Khashoggi’s death, though he also said it was "possible" that powerful Saudi Crown Prince Mohammed bin Salman did not know about the killing of Khashoggi.

Jubeir insisted on Sunday that the operation was not ordered by the Crown Prince.

"This was an operation that was a rogue operation, this was an operation where individuals ended up exceeding their authorities and responsibilities they had; they made a mistake when they killed Jamal Khashoggi in the consulate and they tried to cover up for it," he claimed, adding he is confident the US-Saudi relationship would survive the crisis.

"The strategic relationship is important for both countries," said Jubeir. "I believe when the investigation is over and the facts are revealed, people know who is responsible and see those individuals punished, that the relationship will weather this."

He added that Saudi King Salman was "determined to see this investigation through, determined to ascertain the facts, determined to hold those responsible accountable and determined to put in place policies and procedures in the security services to prevent something like this from ever happening again."