Turkey's justice minister on Thursday renewed a call on Saudi Arabia to cooperate in the investigation into the killing of journalist Jamal Khashoggi at the Saudi Consulate in Istanbul, saying "no one can escape responsibility."

Abdulhamit Gul said that Saudi Arabia's top prosecutor — who spent three days in Istanbul as part of joint Turkish-Saudi efforts to investigate the killing — had failed to answer Turkish investigators' questions about the location of the writer's remains as well as who ordered the killing.

"We expect these questions to be answered swiftly," Gul told reporters. "No one can escape responsibility. This issue has become a world matter. It is not an issue that can be covered up."

He added: "We want the Saudi authorities to enter into close cooperation with us. They have to support (the probe) so that the entire incident is brought to light."

Istanbul's chief prosecutor announced Wednesday that The Washington Post columnist was strangled immediately after he entered the consulate on Oct. 2 to collect a document he needed to marry his Turkish fiancee. His body was dismembered and removed from the consulate, the prosecutor's office stated, adding that the killing was premeditated.

The prosecutor's statement that Khashoggi was killed immediately conflicted with a report by pro-government newspaper Yeni Safak last month, which cited what it described as an audio recording of Khashoggi being tortured before being killed.

Turkey is seeking the extradition of 18 suspects who have been detained in Saudi Arabia so that they can be put on trial in Turkey. They include 15 members of an alleged Saudi "hit squad" that Turkey says was sent to Istanbul to kill the 59-year-old journalist, who lived in exile in the United States and had written critically of Saudi Arabia's Crown Prince Mohammed bin Salman.

Some of those implicated in the killing are close to the prince, whose condemnation of the killing has failed to ease suspicions that he was involved.

Under mounting international pressure, Saudi Arabia has changed its narrative about Khashoggi's killing several times, and has recently acknowledging that Turkish evidence shows it was premeditated.

In Washington on Thursday, the State Department said it backed a call from Khashoggi's family for his remains to be returned to them. Deputy spokesman Robert Palladino told reporters the writer's remains should be located and returned for a proper burial.

Speaking at a forum at Stanford University, Saudi U.N. Ambassador Abdallah Al-Mouallimi said "this is a heinous crime that should be condemned by all people."

But he still described the slaying as an individual crime committed by individual people acting without authority to commit such a crime. He did not offer any evidence of how he could claim the killer or killers acted without government authority.