France, Germany and Britain on Sunday expressed concerns over the disappearance of Saudi journalist Jamal Khashoggi, and called for "a credible investigation" into the incident.

In a joint statement issued by the Quai d'Orsay, top diplomats of the three European countries stressed that "all the light must be shed on the disappearance of... Khashoggi, whose relatives have had no news since October 2," saying they treated the affair "with the utmost seriousness."

"There needs to be a credible investigation to establish the truth about what happened, and, if relevant, to identify those responsible for the disappearance of Jamal Khashoggi, and ensure that they are held to account," said French Foreign Minister Jean-Yves le Drian, German Heiko Maas and British Jeremy Hunt.

"We encourage joint Saudi-Turkish efforts in that regard, and expect the Saudi government to provide a complete and detailed response. We have conveyed this message directly to the Saudi authorities," they added.

Saudi journalist Jamal Khashoggi disappeared during a visit to the Saudi consulate in Istanbul earlier this month.

Media reports said the Washington Post columnist might have been killed or arrested inside the Saudi consulate, which has been denied by the Saudi authorities.