The Nobel Peace Prize laureate Tawakkol Karman said the abduction of Saudi writer and journalist Jamal Khashoggi by the Saudi Consulate in Istanbul provides additional evidence of state terrorism practiced by the Kingdom of fear against its citizens, especially opponents.

"This time, this terrorism took place in Turkish territory, which is considered an infringement of Turkish sovereignty and puts the Turkish government in the face of a difficult test," said Tawakkol Karman, on her official Facebook page.

Karman continued: "If the Turkish government keeps silent about the kidnapping of Jamal Khashoggi in its territory, it will only mean that there is collusion and violation of its responsibilities for protecting its visitors."

Karman called on the Turkish government to do its duty to protect Khashoggi and maintain his safety as a full responsibility for him, from the moment he enters the country until he leaves.

Hatice Cengiz, fiancée of Jamal Khashoggi, told BBC that he had gone to the Saudi Consulate headquarters in Levant in Istanbul on Tuesday afternoon, but he had not come out yet.

Cengiz told BBC that Khashoggi - known for his criticism of the situation in Saudi Arabia - went to the Saudi Embassy to complete some official papers and that she was not allowed to accompany him to the Consulate.

Cengiz told BBC correspondent in Istanbul that Saudi Consulate officials had told her Khashoggi had left the Consulate, but she said all information indicated that Khashoggi was still "being held" inside the Consulate.