He made the remarks while speaking at a parliamentary group meeting of his ruling Justice and Development Party (AKP) here, reports Hurriyet Daily News.

"Turkish security services have evidence that the murder was a planned affair. Turkey and the world will only be satisfied when all the planners and perpetrators are held to account," the President said.

"Other countries must participate in the investigation."

Erdogan claimed that Khashoggi, a Washington Post columnist and a critic of Crown Prince Mohammad Bin Salman, first came to the Saudi consulate in Istanbul on September 28 to get his marriage documents. The "roadmap" to kill Khashoggi started with this visit.

He said that a day before Khashoggi disappeared on October 2, a group of three Saudis landed in Istanbul and went to the consulate while another team visited the Belgrad Forest near the city and the neighbouring Yalova province.

"On October 2, another group came and this 15-member team went to the consulate and removed the hard disks of security cameras there. Khashoggi's went inside that afternoon and never appeared again while his fiancee waited outside," Erdogan said.

It was later found that 15 Saudis including intelligence officers and forensics experts came to Turkey ahead of Khashoggi's visit.

"I spoke to (Saudi) King Salman on October 14 and formed a joint investigation team. This is how our officials could enter the consulate and the consul's residence... Seventeen days after the killing, Saudi Arabia admitted that Khashoggi was killed in the consulate.

"We held another phone call and they told us that 18 Saudis, including people from the 15-member team we exposed, were arrested in Saudi Arabia," he added.

The President said that information and evidence show that Khashoggi fell victim to a brutal murder.

"We have strong evidence that the killing was intentional, not accidental. Now we expect them to punish all those who played a part in the murder."