– Turkish President Recep Tayyip Erdogan demanded Monday that Saudi Arabia prove that journalist Jamal Khashoggi left the Saudi consulate in Istanbul on his own as Saudi officials have repeatedly asserted after he disappeared last week while inside the mission.

Erdogan’s comments were his most direct suggestion yet of potential Saudi culpability in Khashoggi’s disappearance and came after other Turkish officials have said they believe that he was killed by Saudi agents inside the consulate.

“Do you not have cameras and everything of the sort?” Erdogan said of the consular officials. “They have all of them. Then why do you not prove this? You need to prove it.”

Turkey’s foreign ministry summoned the Saudi ambassador to urge “full cooperation” in the investigation into Khashoggi’s disappearance, the official Anadolu news agency said Monday.

The ambassador was called to the ministry in the Turkish capital, Ankara, on Sunday, the agency said. It was the second time Turkey summoned the ambassador since Khashoggi failed to emerge following a visit to the consulate on Oct. 2.

Turkish officials have said they believe Khashoggi, 59, a critic of the Saudi leadership and a contributor to the Washington Post’s Global Opinions section, was killed by a team of 15 Saudis flown in specifically to carry out the attack. Saudi authorities have called the charges “baseless.”

The incident has angered rights activists and press freedom advocates, who have called on the Saudi government to clarify Khashoggi’s whereabouts. It has also raised tensions between regional rivals Turkey and Saudi Arabia.

Turkey has yet to make any evidence public. The private Turkish broadcaster, NTV, reported Monday that police had requested access to the Saudi Consulate in Istanbul. It was unclear whether the police were granted access or if they would search the diplomatic mission in Istanbul’s Levent district at a later date.

A report in the daily newspaper Sabah said investigators were also focused on a convoy of diplomatic vehicles that departed from the consulate on the day Khashoggi vanished.

A U.S. official said that Turkish investigators believe Khashoggi was likely dismembered, removed in boxes and flown out of the country.

In a meeting with the Washington Post’s publisher, Fred Ryan, the Saudi ambassador to the United States said Sunday night that it was “impossible” that such a crime could be covered up by consulate employees “and we wouldn’t know about it.”

The ambassador, Prince Khalid bin Salman, repeated a statement made by other Saudi officials that video cameras at the consulate had not been recording on the day of Khashoggi’s visit. The ambassador declined to discuss the matter further, instead saying, “We don’t want to harm the investigation.” He added, “Speculation does not help our mission.”

Salman said that Khashoggi, who was once close to the ruling family in Saudi Arabia, had “always been honest.” Khashoggi’s criticism of the current Saudi leadership “has been sincere,” adding that he had seen him personally over the past year and had even exchanged text messages with the missing journalist.

During the meeting, Ryan expressed the Post’s “grave concern” about Khashoggi’s disappearance. He said the Post was committed to discovering the truth and that if the investigation showed any Saudi government involvement, the news organization would view it as a flagrant attack on one of its journalists.

Khashoggi had entered the consulate to obtain a document related to his upcoming wedding, according to his fiancée, Hatice Cengiz.

She waited outside for hours and called the police when he did not emerge. Khashoggi had been living in self-imposed exile in the United States since 2017, when he fled Saudi Arabia for fear of arrest.