The killing of journalist Jamal Khashoggi at the Saudi consulate in Istanbul was a "rogue operation", Saudi Arabia's foreign minister said.
Adel al-Jubeir said that those responsible will be held accountable for "this huge and grave mistake".
He extended his condolences to the family of the journalist.
"We can feel their pain and we wish this didn't happen and I wish that this could have been avoided," he said in an interview with Fox News.
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His comments came as it was reported that Mr Khashoggi's fiancee has been given 24-hour police protection.
Saudi Arabia finally admitted on Friday that its agents killed Mr Khashoggi after he entered the consulate on October 2, but denies that Crown Prince Mohammed bin Salman or King Salman were involved.
Mr Al-Jubeir echoed President Donald Trump's warnings against rushing to judge Saudi leaders, saying "there is the presumption of innocence until proven guilty," and that some have "turned that upside down".
He added that Saudi officials do not know the whereabouts of Mr Khashoggi's remains.
The kingdom has also said 18 suspects are in custody and that intelligence officials have been fired.
Dominic Raab said on Sunday that he did not think Saudi Arabia’s account of Khashoggi’s death was “credible”.
“No, I don’t think it’s credible,” he told the BBC’s Andrew Marr Show.
But he added that, as British jobs depended on maintaining a relationship with Saudi Arabia, the UK would not be terminating its dealings with the kingdom.
“We are not throwing our hands in the air and terminating the relationship with Saudi Arabia, not just because of the huge number of British jobs that depend on it but also because if you exert influence over your partners you need to be able to talk to them,” Mr Raab said.