A court in Istanbul has issued arrest warrants for two top Saudi officials, both former advisors to Crown Prince Mohammed bin Salman, over the killing of dissident writer Jamal Khashoggi, state news agency Anadolu reported on Wednesday.

The Istanbul chief public prosecutor's office asked the court to issue the arrest warrants, citing "strong suspicion" that Ahmed al-Asiri, former deputy chief of the intelligence service, and Saud al-Qahtani, a former close adviser to Mohammed, were among the planners of the murder.

Khashoggi, a Saudi national and a vocal critic of Mohammed, was killed inside Saudi Arabia's consulate in Istanbul on October 2. Saudi officials have repeatedly denied reports that the crown prince is linked to the murder.

Khashoggi's remains have not yet been located.

The Istanbul prosecutor's office cited "new evidence" as part of its ongoing probe to charge the two people with "planned and deliberate murder with monstrous intent or torture," according to Anadolu.

The office separately identified 15 alleged members of a hit squad who travelled to Istanbul to kill Khashoggi as well as three Saudi consulate employees. All 18 left Istanbul following the murder, it added.

Turkish President Recep Tayyip Erdogan has kept the pressure on Riyadh to reveal the perpetrators behind Khashoggi's killing.

It is in Saudi Arabia's best interest to disclose what exactly happened to Khashoggi, the Turkish president told reporters in Argentina over the weekend, adding that Turkey had shared information related to the killing with several countries, including Germany and the United States.

On Tuesday, two US senators who attended a briefing by CIA director Gina Haspel on the killing of Jamal Khashoggi said they no longer had any doubt that the Saudi crown prince was responsible for the dissident's murder.

If Mohammed were in front of a jury, "he would have a unanimous verdict in about 30 minutes. Guilty. A guilty verdict," Senator Bob Corker said.

Saudi Arabia has opened its own investigation into the murder and is seeking the death penalty for five suspects. It continues to insist it was a "rogue operation" carried out without the knowledge of the crown prince. 

Erdogan has repeatedly demanded that those currently detained in Saudi Arabia be extradited to Turkey.

The two Saudi suspects sought by Turkey are not among those detained in the kingdom.