Turkish prosecutors have opened an investigation into the disappearance of a missing Saudi journalist.
Jamal Khashoggi, a critic of Saudi Arabia's Crown Prince Mohammed bin Salman, has not been seen since Tuesday, when he entered the Saudi consulate in Istanbul.
Turkish sources quoted by Reuters and the Washington Post say they believe he has been killed inside the consulate.
They did not give any evidence for the claim, nor suggest how he was killed.
Saudi officials have not yet commented, however a source at the consulate - also quoted by Reuters - described the accusations as baseless.
The source added that a security team had arrived in Istanbul to investigate Mr Khashoggi's disappearance.
Earlier, Prince bin Salman told Bloomberg News that Turkish authorities were welcome to search the building.
Turkish media said prosecutors were now looking closely at the case, although this may be a widening of an inquiry begun on Tuesday.
The two unnamed sources said on Saturday that the initial assessment of police was that Mr Khashoggi had been killed at the consulate.
"We believe that the murder was premeditated and the body was subsequently moved out of the consulate," one of the sources told Reuters.
A source quoted by The Washington Post said the journalist was killed by a 15-member Saudi team sent "specifically for the murder".
The BBC's Mark Lowen says that, if confirmed, the state-sponsored murder on Turkish soil of a high-profile Saudi dissident would worsen already strained relations between Turkey and Saudi Arabia.
Turkey has taken the side of Qatar over its blockade by Saudi Arabia and other neighbours, and Turkey's rapprochement with Iran has riled the government in Riyadh.
Reuters earlier quoted the Turkish ruling party as saying the investigation would be comprehensive and that the government's sensitivity about the case was at the "highest level". The AK Party said Mr Khashoggi's whereabouts would be uncovered.
The head of the Turkish-Arab Media Association told the New York Times that Turkish police officers providing security for the consulate had checked their security cameras and did not see the journalist leave on foot. But Turan Kislakci added that diplomatic cars had been seen moving in and out.
On Wednesday, the Turkish foreign ministry summoned Saudi Arabia's ambassador and asked for an explanation about the disappearance.
BBC Online
BDST: 0959 HRS, OCT 7, 2018
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