Chancellor Angela Merkel said Germany needed more evidence if it was to class the movement of U.S.-based cleric Fetullah Gulen, blamed by Turkey for the 2016 failed coup, as a "terrorist" organisation as Ankara is demanding.

Speaking at a Berlin news conference with Turkish President Tayyip Erdogan, Merkel also said Germany was seeking several individuals whose extradition on "terrorism" charges Turkey was demanding, but it was not certain that they were in Germany.

"We take very seriously the evidence Turkey provided but we need more material if we are to classify it in the same way we have classified the (Kurdish) PKK," she told reporters on Friday.