Police searching the Saudi consulate have found evidence that Saudi writer Jamal Khashoggi was killed there, a high-level Turkish official said.

The revelation came as America’s top diplomat landed in Turkey to discuss the probe into the writer’s disappearance.

The Turkish official’s comment has intensified pressure on Saudi Arabia to explain what happened to Mr Khashoggi, who vanished on October 2 while visiting the consulate to pick up paperwork he needed in order to get married.

Saudi consulate
Mr Khashoggi is thought to have been murdered inside the consulate (AP)

US secretary of state Mike Pompeo told journalists before leaving Riyadh that Saudi leaders, including King Salman and his son, the 33-year-old Crown Prince Mohammed bin Salman, “made no exceptions on who they would hold accountable”.

Mr Pompeo said: “They made a commitment to hold anyone connected to any wrongdoing that may be found accountable for that, whether they are a senior officer or official.”

However, no major decision is made outside of the ultra-conservative kingdom’s ruling Al Saud family.

Mr Khashoggi also fled the country last year amid the rise of Prince Mohammed, whom he wrote critically about in The Washington Post.

A strongly pro-government Turkish newspaper published a gruesome recounting of the alleged murder of Mr Khashoggi inside the consulate.

Yeni Safak cited what it described as an audio recording of the killing, which it said showed the Washington Post columnist was tortured.

The newspaper said Saudi Consul General Mohammed al-Otaibi could be heard on the tape, telling those allegedly torturing Mr Khashoggi: “Do this outside; you’re going to get me in trouble.”

The newspaper said one of the Saudis torturing Mr Khashoggi replied: “Shut up if you want to live when you return to (Saudi) Arabia.”

The consulate
Inquiries are continuing into the disappearance (AP)

Meanwhile, US president Donald Trump, who earlier warned of “severe punishment” if the kingdom was found culpable for Mr Khashoggi’s appearance, criticised the global condemnation against the kingdom and compared it to the allegations of sexual assault levelled against US supreme court Justice Brett Kavanaugh during his confirmation hearing.

Mr Trump said: “Here we go again with ‘you’re guilty until proven innocent’.”

That attitude does not appear to be shared with US congress, as one prominent Republican senator said he believed that the crown prince, widely known as MBS, had Mr Khashoggi “murdered”.

“This guy has got to go,” said Senator Lindsey Graham, a Republican from South Carolina, speaking on Fox television.

“Saudi Arabia, if you’re listening: There are a lot of good people you can choose, but MBS has tainted your country and tainted himself.”

US attorney general Jeff Sessions said “serious evaluation” was being given to whether US law enforcement officials would aid in the investigation over Mr Khashoggi’s disappearance.

Saudi consulate
A Turkish official has said police found evidence Mr Khashoggi was killed at the Saudi consulate (AP)

Saudi officials have called Turkish allegations that a team of 15 Saudi agents killed Khashoggi “baseless”, but US media reports suggested that the kingdom may acknowledge the writer was killed at the consulate, perhaps as part of a botched interrogation.

Washington Post publisher and CEO Fred Ryan said the Saudi government “owes the Khashoggi family and the world a full and honest explanation of everything that happened to him”, noting that Tuesday marked two weeks since the disappearance of the 59-year-old journalist.

“The Saudi government can no longer remain silent, and it is essential that our own government and others push harder for the truth,” Mr Ryan added.

The high-level Turkish official told the AP that police found “certain evidence” of Mr Khashoggi’s killing at the consulate, without elaborating.

Police plan a second search at the Saudi consul general’s home, as well as some of the country’s diplomatic vehicles, Turkish foreign minister Mevlut Cavusoglu said. Leaked surveillance video shows that diplomatic cars travelled to the consul general’s home shortly after Mr Khashoggi went into the consulate.

Saudi consulate in Istanbul
A protest takes place outside the consulate (AP)

UN human rights chief Michelle Bachelet said the “inviolability or immunity” of people or premises granted under the 1963 Vienna Convention on Consular Relations “should be waived immediately”.

That convention covers diplomatic immunity, as well as the idea that embassies and consulates sit on foreign soil in their host countries.

“Given there seems to be clear evidence that Mr Khashoggi entered the consulate and has never been seen since, the onus is on the Saudi authorities to reveal what happened to him,” Ms Bachelet said.

Nils Melzer, the UN special investigator on torture, said that if Turkey and Saudi Arabia cannot conduct “a credible and objective investigation”, then international involvement may be needed.