The disappearance of a prominent critic of Saudi Arabia's rulers after entering the kingdom's Istanbul consulate risks severely tarnishing the reformist image of its de facto leader Crown Prince Mohammed bin Salman, experts say.
On Sunday, Turkish Deputy Minister Sedat Onal summoned the Saudi ambassador to Turkey to the foreign ministry for a second time since Khashoggi's disappearance, sources at the ministry told Al Jazeera.
She said Mr Khashoggi was required to surrender his mobile phone, which is standard practice in some diplomatic missions.
"God willing we will not be faced with a situation we do not want", the president told reporters in Ankara, adding: "I still am hopeful".
"I have raised Jamal's disappearance personally with the Saudi ambassador, and while we await more information, know we will respond accordingly to any state that targets journalists overseas", he wrote.
Turkish officials have said privately they believe Mr Khashoggi was murdered and dismembered inside the consulate but Turkey's government has not publicly made the explosive accusation.
Erdogan said the Saudi consulate should have surveillance cameras and should be able to show the video of Khashoggi leaving the building.
The consulate rejected the claims that the journalist was killed there as "baseless", in a Twitter message.
Saudi Arabia, naturally, has denied any involvement.
Meanwhile, press freedom groups and human rights organizations continued their call for more information about Khashoggi's case and his alleged slaying.
Dujarric told reporters at United Nations headquarters in NY on Monday that Guterres "has been an advocate for journalists".
Self-exiled Saudi dissident Jamal Khashoggi said earlier this year that the Saudi government has been moving toward nationalist radicalism. He was seeking to secure documentation for his forthcoming marriage when he entered the Saudi consulate in Istanbul.
Khashoggi's fiancee, Hatice Cengiz, said he first went to the consulate at September 28 to obtain a document related to their upcoming wedding and he returned Tuesday with concern he wouldn't be allowed to leave.
"The United States must now make a concerted effort to determine all the facts about Mr Khashoggi's disappearance", the Post said in an editorial, imploring Washington to "demand answers, loud and clear". "Our expectation of full cooperation during the investigation process [on missing journalist] was conveyed to him", said a diplomatic source.
Yemeni activist Tawakkol Karman, the 2011 Nobel Peace Prize laureate, said it would be an "awful crime" if the claims of his death were true.
The woman named "Khadijah" who is promoting herself as Jamal's fiancé, is not known by the family and she is not his fiancé: Motasem Khashoggi, who is representing Jamal Khashoggi's family.
Khashoggi is a former advisor to Saudi intelligence and was highly critical of the kingdom's war in Yemen as well as a recent crackdown on dissent.
His interview came a day after Trump told a cheering crowd of supporters at a rally in Southaven, Mississippi, that Saudi King Salman would not last in power unless the U.S. provided military support for the Arab kingdom.