A veteran Saudi journalist who has been critical of the government has gone missing after visiting the kingdom’s consulate in Istanbul on Tuesday, the Washington Post reported.

Jamal Khashoggi, who writes opinion pieces for the Post, has not been seen since entering the consulate in the afternoon, according to his fiance who accompanied him but waited outside until it closed, the newspaper said.

Khashoggi, a former government advisor who went into self-imposed exile in the United States last year to avoid possible arrest, has been critical of some of the policies of Saudi Crown Prince Mohammed bin Salman and Riyadh’s intervention in the war in Yemen.

“We have been unable to reach Jamal today and are very concerned about where he may be,” the Post’s international opinions editor Eli Lopez said in a statement.