U.S. President Donald Trump and his Turkish counterpart Recep Tayyip Erdogan discussed how to respond to the killing last month of Saudi dissident Jamal Khashoggi, a White House official said on Sunday.

The conversation took place during a Saturday dinner with heads of state gathered in Paris to mark the World War One Armistice centenary.

Khashoggi, a critic of ruling Saudi Crown Prince Mohammed bin Salman, was murdered at the kingdom’s Istanbul consulate by a team sent from Riyadh. Saudi authorities have acknowledged that the killing was premeditated, but his body has not been found.

The Trump administration had previosly insisted it is demanding full accountability from Riyadh in Khashoggi's death. In what it called a first step, it revoked the visas of some Saudi officials implicated in the slaying.

Erdogan revealed on Saturday that audio recordings of the killing had been given to the U.S., French, German and British governments, adding that the operation had been ordered at the “highest levels” of the Saudi government.

Trump expects to form a “much stronger opinion” by next week on Khashoggi’s killing and Washington’s response, he said on November 7 - adding that he was working with Congress, Turkey and Saudi Arabia to establish who bore responsibility.