The King of Saudi Arabia and the Crown Prince sent their condolences to a son of Jamal Khashoggi, a journalist who died at his country's consulate in Istanbul, Saudi state media reported.

The official Saudi Press Agency (SPA) said on Sunday that the Monarch, Salman bin Abdulaziz, and his son, Mohammed bin Salman, telephoned Salah Jamal Khashoggi to express their condolences, reports Efe news.

Salah thanked the king and expressed his "sincere gratitude" to Prince Mohammed for the calls, according to separate press releases published by the SPA.

Saudi Arabia's Minister of Foreign Affairs Adel al-Jubeir said in an interview with US television channel Fox on the same day that Prince Mohammed had no knowledge of Khashoggi's death.

In that interview, al-Jubeir described the death of Khashoggi as "a grave mistake" and said that those responsible will be held to account.

The Saudi authorities at first denied the death of the regime-critical journalist.

On Saturday, the Saudi authorities said that Khashoggi died in the course of a "fight" with agents who were trying to interrogate him in the legation.

The UK, France and Germany said on Sunday that Saudi Arabia's version of Khashoggi's death needs to be supported by "facts" to be considered "credible".

German Chancellor Angela Merkel announced the suspension of weapons sales to Saudi Arabia on the grounds that they cannot be done under the "current circumstances", in reference to the Khashoggi case.

Turkish President Recep Tayyip Erdogan announced that he will reveal details about the Turkish investigation of the alleged murder of the journalist on Tuesday.

Khashoggi, a columnist for The Washington Post, had been missing since he entered the Saudi consulate in Istanbul on October 2.