Britain's former Prime Minister Tony Blair arrives for an event at Thomson Reuters in London, Britain, October 11, 2018. REUTERS/Simon Dawson

LONDON (Reuters) - Former British Prime Minister Tony Blair said on Thursday that the disappearance of journalist Jamal Khashoggi was extremely troubling and went against the spirit of the reforms advocated by Saudi Crown Prince Mohammed bin Salman.

Khashoggi was last seen on Oct. 2 entering the Saudi consulate in Istanbul to get documents for his forthcoming marriage. His fiancée, waiting outside, said he never emerged and Turkish sources said they believe Khashoggi was killed in the building.

“There is no doubt at all as the American administration and the British government have made clear this is an extremely troubling situation,” Blair said at a Reuters Newsmaker in London.

“I know the Saudi government have issued a very strong denial, but the thing has to be properly investigated and explained,” Blair said.

“This issue has to be resolved because otherwise it runs completely contrary to that process of modernization.”