Saudi Arabia has said the journalist Jamal Khashoggi - who went missing more than two weeks ago – is dead, blaming a “fight” inside the nation’s consulate in Istanbul.

Quoting the results of the preliminary investigation from the nation’s public prosecutor, the government-controlled al-Akhbariya television said Mr Khashoggi died unintentionally during a “fist fight” with people who “met him during his presence at the consulate” on 2 October. However, it did not disclose where his remains were taken.

It also announced that King Salman has dismissed deputy intelligence chief Ahmed al Assiri and Crown Prince Mohammed bin Salman’s nearest adviser, Saud al-Qahtani, who oversees the kingdom’s communications strategy, as part of the investigation. It added that 18 more suspects have been arrested and remain under investigation..

It is the first time Saudi officials have admitted the journalist is dead, having initially claimed Mr Khashoggi left the consulate after his visit. The last time the Washington Post columnist was seen alive was entering the diplomatic residence.

In addition to the dismissals and arrests, King Salman announced a plan to restructure the kingdom’s intelligence services. Spearheading the effort will be Crown Prince Mohammed bin Salman.

The explanation follows repeated denials from senior Saudi officials that Riyadh had anything to do with Mr Khashoggi’s disappearance. Turkish officials have alleged that Mr Khashoggi was murdered in the consulate by a Saudi-linked hit squad – something Saudi Arabia has also denied.

US President Donald Trump called the Saudi explanation "credible" and that the arrests were important and "a good first step" but said what happened in Istanbul was "unacceptable". He added that he would like to speak to the crown prince before next steps are taken.

The president has faced pressure from Congress to ensure a robust response from Washington, but he appears reticent to upset a strategic ally and trade partner.

Mr Trump said that he will work with Congress on what the US response should be, but said that that he would prefer not to hurt American companies and jobs by cutting billions of dollars in arms sales to the kingdom.

Khashoggi disappearance: Forensic police investigate Saudi consul Show all 12 1 /12 Khashoggi disappearance: Forensic police investigate Saudi consul Khashoggi disappearance: Forensic police investigate Saudi consul According to local media reports, Saudi consul Mohammad al-Otaibi left Turkey on 16 October. A Turkish prosecutor on 15 October has entered the Saudi consulate in Istanbul to investigate the disappearance of dissident Saudi journalist Jamal Khashoggi, an inspection that was being carried out jointly with a Saudi team AFP/Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul Turkish forensic police officers work on the roof of the residence of the Saudi consul in Istanbul EPA Khashoggi disappearance: Forensic police investigate Saudi consul Khashoggi went missing on 2 October when he entered the Saudi consulate to pick up paperwork AP Khashoggi disappearance: Forensic police investigate Saudi consul ISTANBUL, TURKEY - OCTOBER 17: Turkish police arrive to investigate the Saudi Arabian consulate general residence as investigations continue into the disappearance of journalist Jamal Khashoggi on October 17, 2018 in Istanbul, Turkey. Turkish police first entered and searched the Saudi Arabian consulate on October 15 amid a growing international backlash about the disappearance. Khashoggi, a U.S. resident and critic of the Saudi regime, has been missing since visiting the Saudi Arabian consulate on October 2. Turkish officials have said they believe he was killed inside. (Photo by Chris McGrath/Getty Images) ***BESTPIX*** Chris McGrath Khashoggi disappearance: Forensic police investigate Saudi consul Turkish forensic and investigation officers arrive at Saudi Consul's residence on October 17, 2018 in Istanbul. - Saudi Arabia's consul to Istanbul Mohammed al-Otaibion on October 16, 2018 left the Turkish city bound for Riyadh on a scheduled flight, reports said, as Turkey prepared to search his residence in the probe into the disappearance of journalist Jamal Khashoggi. (Photo by OZAN KOSE / AFP)OZAN KOSE/AFP/Getty Images OZAN KOSE AFP/Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul Turkish police arrive to investigate the Saudi Arabian consulate general residence Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul Turkish forensic police search for evidence at the garden of the Saudi Arabia's Consul General Mohammad al-Otaibi AFP/Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul Turkish police search the rooftop of the Saudi Arabian consulate general residence Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul Turkish police arrive at the residence of the Saudi consul General Mohammed al-Otaibi to conduct a search AP Khashoggi disappearance: Forensic police investigate Saudi consul Turkish police officers gather as they prepare to enter Saudi Arabia consul's residence, in Istanbul, Wednesday, Oct. 17, 2018. America's top diplomat is in Turkey, where a strongly pro-government newspaper has published a gruesome recounting of the alleged slaying of Saudi writer Jamal Khashoggi at the Saudi Consulate in Istanbul. (AP Photo/Petros Giannakouris) Petros Giannakouris AP Khashoggi disappearance: Forensic police investigate Saudi consul Turkish forensic police search for evidence at the garden of the Saudi Arabia's Consul General Mohammad al-Otaibi AFP/Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul ISTANBUL, TURKEY - OCTOBER 17: Turkish police search the rooftop of the Saudi Arabian consulate general residence as investigations continue into the disappearance of journalist Jamal Khashoggi on October 17, 2018 in Istanbul, Turkey. Turkish police first entered and searched the Saudi Arabian consulate on October 15 amid a growing international backlash about the disappearance. Khashoggi, a U.S. resident and critic of the Saudi regime, has been missing since visiting the Saudi Arabian consulate on October 2. Turkish officials have said they believe he was killed inside. (Photo by Chris McGrath/Getty Images) Chris McGrath Getty Images

However, the Saudi explanation will likely do little to quell critics and other nations. It remains to be seen whether punitive sanctions will be forthcoming from the international community, or whether the narrative from Riyadh will be accepted.

UN secretary general Antonio Guterres said he was “deeply troubled” by the development and called for a “prompt, thorough, transparent” probe into the circumstances of Mr Khashoggi’s death.

The admission will also weaken the crown prince, who has drawn criticism and generated enemies inside and outside the kingdom for his brash tactics and what many describe as reckless geopolitical moves. However, the explanation does offer some insulation for royal family and means the crown prince will probably survive and remain heir to the throne for now.

The affair has badly tarnished Saudi Arabia’s image worldwide. Dozens of businesses, thinktanks, educational institutions, and political leaders across the world have spoken out over Mr Khashoggi.

Representatives form a number of nations – including the UK, US and France – have pulled out of a major economic conference in Riyadh later this month amid calls for answers.

“It will have a lasting effect on Saudi Arabia,” a journalist at a leading pro-government Saudi newspaper told The Independent. “They have to work all over again on a new page with respect to the state image. We have lost a lot.”

Donald Trump: 'certainly looks like' missing Saudi journalist Jamal Khashoggi is dead

Saudi Arabia’s official news agency cited a source saying the kingdom began investigating Mr Khashoggi’s disappearance on 6 October, when it dispatched a team of ranking officials to collaborate with Turks. King Salman ordered the Saudi prosecutors to investigate the disappearance on 12 October. The report said that “suspects” travelled to Istanbul to meet with Mr Khashoggi “as there were indications of the possibility of his returning back to the country”.

But things went wrong, and “discussions” took a negative turn that “led to a fight and a quarrel between” with Mr Khashoggi, leading to his death and the suspects’ “attempt to conceal and cover what happened”.

The report said “the kingdom expresses its deep regret at the painful developments that have taken place and stresses the commitment of the authorities in the kingdom to bring the facts to the public opinion, to hold all those involved accountable and bring them to justice by referring them to the competent courts in the Kingdom of Saudi Arabia”.

Security camera footage and passport control data released by Turkish authorities to local media suggested 15 Saudi nationals, at least some of them tied to the upper echelons of Riyadh’s security apparatus, had arrived in Istanbul and headed to the consulate, hours before Mr Khashoggi’s scheduled visit, then hastily headed back to the airport as news of the Washington Post columnist’s disappearance spread.

Quoting an unnamed Saudi official familiar with the investigation, Reuters reported the possibility of “a standing order” to “bring critics back to” Saudi Arabia that may have been “aggressively interpreted” by the individuals in the consulate. The official claimed that Crown Prince Mohammed “had no knowledge” of the circumstances surrounding Mr Khashoggi’s death.

Earlier, police in Turkey expanded their search for Mr Khashoggi’s body, with unnamed officials saying his body may have been disposed of in the nearby Belgrad forest or on farmland.

The admission of Saudi culpability, however, represents a significant win for Turkey, which has been doling out incriminating leaks about the case while its top officials, including President Recep Tayyip Erdogan, maintained a facade of diplomatic politesse with Saudi counterparts.

Indeed, the reports on Saudi state media followed shortly after King Salman spoke on the phone with Mr Erdogan about the case.

The pair exchanged information and agreed to continue cooperation into the investigation, Turkish presidential sources said.

“Erdogan is a winner on this one – his first real diplomatic success in many years,” Selim Sazak, a US-based Turkey expert at Brown University, said. Mr Sazak is often a harsh critic of Mr Erdogan.

Mr Sazak said the idea of blaming rogue elements within the security apparatus of being behind Mr Khashoggi’s death originated with the Turks and offered up as a face-saving way to resolve what was turning into a massive diplomatic crisis. Mr Erdogan has long sought to weaken the crown prince, whom he considers a dangerous upstart. Turkish media reported that Mr Erdogan and King Salman spoke overnight on Friday

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“Since day two, Turkey was like “Jamal is dead but maybe it wasn’t you? Maybe it was someone rogue. It was the rogues, right?’” said Mr Sazak. “Then the Americans signed on. It was the Saudis digging their heels because humble pie is on the menu at MbS’s court tonight, and he probably doesn’t like how it tastes.”

Mr Sazak speculated that the Turkish government would also be satisfied with the Saudi explanation, despite suggestions of a possible whitewash. “They’ll hang a few of these guys and that’ll be that,” he said.

As for the US, it is clear Congress will not let Mr Trump drop the issue. Adam Schiff of California, the ranking Democrat on the House intelligence committee, said that if Mr Khashoggi was fighting inside the consulate, he was “fighting for his life with people sent to capture or kill him”. He added that If Mr Trump’s administration will not hold Saudi Arabia accountable for Mr Khashoggi’s death, Congress will.