Ankara, Oct 11 (IANS): Turkish President Recep Tayyip Erdogan on Thursday expressed concern about the fate of Jamal Khashoggi, the dissident Saudi journalist who disappeared from his country's consulate in Istanbul last week.

The 59-year-old Saudi national has not been heard from since he entered the consulate building on October 2 for paperwork required to marry his Turkish fiancée, Hatice Cengiz, with Turkish press claiming the journalist was either kidnapped or murdered inside the facility.

Saudi Arabia denies this.

On a flight back from Hungary, Erdogan was cited by media as saying that Turkey could not remain silent over Khashoggi's disappearance, stressing the authorities were investigating the case in all its dimensions.

The Turkish leader rejected commenting on allegations that Khashoggi was killed at the consulate, but said he was worried, Efe news reported.

Erdogan added that US President Donald Trump had also voiced his worries over the matter. The US leader said on Wednesday that he had talked to the Saudi authorities "at the highest level" about Khashoggi.

"We cannot let this happen to reporters, to anybody... We're demanding everything. We want to see what's going on there," Trump said.

The White House said Secretary of State Mike Pompeo and senior officials had spoken to Saudi Crown Prince Mohammed Bin Salman and asked for more details about the situation.

Khashoggi distanced himself from the Saudi monarchy in 2017 and lived in self-imposed exile in the US, where he began writing op-eds for the Washington Post criticizing his country's royal institutions.