ISTANBUL — Turkey is seeking the arrest of two former aides to Saudi Crown Prince Mohammed bin Salman who were dismissed amid the fallout from the killing of Washington Post columnist Jamal Khashoggi.

The U.N.'s human rights chief, meanwhile, said an international probe is needed into Khashoggi's death.

Turkey's official Anadolu news agency said Wednesday a court approved arrest warrants for former royal court adviser Saud al-Qahtani and former deputy intelligence chief Ahmed al-Assiri, who are believed to have overseen the team that killed and dismembered Khashoggi at the kingdom's Istanbul consulate in October. Saudi authorities say the agents who killed Khashoggi exceeded their authority.

The Istanbul chief prosecutor's Tuesday court application says there is "strong suspicion" the two aides were involved in planning the killing.

Turkey has been seeking to extradite 18 suspects, including 15 members of the alleged assassination squad. The government says a trial in Turkey would provide transparency and accountability and says Saudi authorities have not fully cooperated with the probe.

Speaking in Brussels, Turkey's Foreign Minister Mevlut Cavusoglu said Wednesday that Turkey had been "patiently" requesting information from the Saudi investigation. He said Saudi Arabia instead gave "contradictory statements" and called on the kingdom "to be transparent towards us and the international community, share what has resulted from the investigations."

Speaking on condition of anonymity in line with government protocol, a senior Turkish official familiar with the investigation said the arrest warrants reflect Turkey's view that Saudi Arabia won't hold the suspects accountable.

"The international community seems to doubt Saudi Arabia's commitment to prosecute this heinous crime," the official said, adding that by extraditing all suspects to Turkey, "Saudi authorities could address those concerns."

Saudi Arabia has detained 21 people and says it is seeking the death penalty for five. Saudi authorities initially said Khashoggi, who had written articles critical of the crown prince's policies, had disappeared after safely leaving the consulate. It only acknowledged he was killed after Turkish press reports based on intelligence leaks revealed extensive details of the operation.

Khashoggi had visited the consulate on Oct. 2 to obtain documents required to wed his Turkish fiancée. His remains are still to be found, and Turkey has repeatedly demanded that Saudi officials reveal the identity of a local collaborator who may have disposed of the body.

U.S. intelligence assessments and experts say it's unlikely the killing could have happened without the crown prince's knowledge.

U.N. human rights chief Michelle Bachelet said an international investigation is needed into the "awful" killing of Khashoggi.

Speaking at a news conference in Geneva timed for the 70th anniversary of the Universal Declaration of Human Rights, she alluded to similar calls from outside experts linked to the U.N. human rights office.

"We also call for an international investigation," she said. "We mentioned to the (U.N.) secretary-general that we thought it was needed, a criminal investigation — international investigation."

She said her office doesn't have the mandate to conduct a criminal investigation, however.

Cavusoglu said if needed, Turkey would not refrain from an international investigation, adding that he discussed it with counterparts at NATO meetings and President Recep Tayyip Erdogan with world leaders during last week's G20 summit.