Pressure is growing on Saudi Arabia to explain the fate of journalist Jamal Khashoggi, as US Secretary of State Mike Pompeo met King Salman in Riyadh.
Mr Khashoggi was last seen at the Saudi consulate in Istanbul two weeks ago.
Turkish officials believe Mr Khashoggi was murdered by Saudi agents but the Saudis have denied this.
However, US media are reporting that the Saudis may be preparing to admit that Mr Khashoggi died as a result of an interrogation that went wrong.
Overnight, Turkish police completed a search of the consulate after being admitted by Saudi authorities.
What's likely to come from the Pompeo meeting?
The secretary of state and the king have now met in Riyadh.
While much of what was discussed has yet to be announced, the US State Department said that Mr Pompeo had used the time to thank the king for his "commitment to a thorough, transparent investigation" into Mr Khashoggi's disappearance.
Mr Pompeo was also expected to seek further clarification over a conversation between the king and President Donald Trump on Monday.
Tweeting earlier about the call, Mr Trump said: "Just spoke to the king of Saudi Arabia who denies any knowledge of whatever may have happened 'to our Saudi Arabian citizen'."
He later told reporters: "The denial was very, very strong. It sounded to me like maybe these could have been rogue killers. Who knows?"
Just spoke to the King of Saudi Arabia who denies any knowledge of whatever may have happened “to our Saudi Arabian citizen.” He said that they are working closely with Turkey to find answer. I am immediately sending our Secretary of State to meet with King!— Donald J. Trump (@realDonaldTrump) October 15, 2018
There is a lot at stake given the strength of Saudi-US ties. Mr Trump has already ruled out cancelling a lucrative arms deal, although he did threaten "severe punishment" if the kingdom were found to be responsible for the death.
King Salman ordered an investigation into the missing journalist on Monday. Saudi statements up to now have dismissed allegations of a killing as "baseless" and "lies".
The kingdom has also angrily rejected what it called political and economic "threats", saying it would respond to any punitive action, such as sanctions, "with a bigger one".
Mr Pompeo is also expected to meet Crown Prince Mohammed bin Salman during his day in Riyadh. The secretary of state may then head to Turkey.
What is this US media line about?
It appeared in the New York Times and on CNN, quoting unnamed sources.
They said Saudi Arabia would acknowledge that Mr Khashoggi's death was the result of an interrogation that went wrong and the intention had been only to abduct him from Turkey.
This may explain in part Mr Trump's "rogue killers" line.
Who such killers could be and how it fits into reports of a Saudi team being despatched to the consulate before Mr Khashoggi's arrival will presumably need to covered.
CNN said the Saudis may argue the operation was conducted without clearance and those responsible would be held accountable.
The Khashoggi family in Saudi Arabia issued a statement calling for an "independent and impartial international commission".
Reputations may be forever tainted
By Frank Gardner, BBC News
The recent, highly charged exchange of words between Washington and Riyadh now appears to have given way to a mutual search for the least bad explanation. Both countries' leaders know they have an enormous amount to lose if this affair ended up splitting apart their 73-year old strategic partnership.
Iran, as the regional rival to Saudi Arabia, would be the prime beneficiary if the Saudis were to lose their defensive US umbrella. President Trump is also correct when he says thousands of US jobs would be lost, with China and Russia to be among those lining up to replace them.
Which begs the wider question: is the West's relationship with Saudi Arabia so important that it outweighs the need to condemn and punish what many believe was a state-sponsored murder of a journalist inside a consulate?
Hence the urgent dispatching of US Secretary of State for talks with the Saudi leadership. In private there may well be some strong words, in public both countries may want to present a united stand. But one thing is certain: whatever narrative emerges, the international reputation of the Saudi Crown Prince and power-behind-the-throne Mohammed Bin Salman will forever be tainted by this affair.
What happened with the consulate search?
For the first time since the journalist disappeared on 2 October, Turkish investigators were allowed to enter the building.
A Saudi team entered first on Monday, followed roughly an hour later by Turkish forensic police.
The Turkish investigators, some wearing overalls, gloves and covered shoes. stayed for about eight hours, leaving in the early hours of Tuesday.
They reportedly took with them samples, including of soil from the consulate garden.
Saudi Arabia agreed last week to allow Turkish officials to conduct a search but insisted it would only be a superficial "visual" inspection.
Turkey rejected that offer. The Sabah daily newspaper said investigators had wanted to search the building with luminol, a chemical which shows up any traces of blood. It is not clear whether that happened.
Reports on Tuesday said Istanbul police would also search the Saudi consul's residence.
What allegedly happened in Istanbul?
Mr Khashoggi, a critic of the Saudi government who has written for the Washington Post, was last seen walking into the consulate on 2 October.
Reports suggest an assault and struggle took place in the consulate after Mr Khashoggi went to get paperwork for his forthcoming marriage.
Turkish sources allege he was killed by a 15-strong team of Saudi agents but Riyadh insists that he left the consulate unharmed.
Mr Khashoggi was once an adviser to the Saudi royal family but fell out of favour with the Saudi government and went into self-imposed exile. He is a US resident.