Qatar demands Saudi Arabia release missing citizens amid Khashoggi controversy

Qatar's semi-independent National Human Rights Committee [NHRC] made the demand on Sunday in a statement carried by the official QNA news agency.

NHCR head Ali bin Samikh al-Marri called for a United Nations probe "into the fate of the three Qatari victims of enforced disappearance and another citizen who was arbitrarily detained".

"The fate of the four Qatari nationals remains unknown since they were arbitrarily and unfairly detained by Saudi authorities,"

Marri slammed the Saudi actions as "shameful and inhumane" and urged the international community to exert pressure on Riyadh to respect international law and release the detainees.

Four Qataris have been arrested in Saudi Arabia since the outbreak of the Gulf crisis, which pits a Saudi-led bloc against Doha.

In June, Saudi authorities arrested a Qatari man as he performed pilgrimage to Islam's holiest site on "terror charges".

The statement comes as Riyadh has come under fire over the disappearance of journalist Khashoggi, with Western states and companies moving to distance themselves from the Gulf State.

US President Donald Trump has threatened the kingdom with "severe punishment" if Khashoggi, who has been critical of powerful Crown Prince Mohammed bin Salman, was killed inside its Istanbul mission.

But Riyadh vowed to hit back on Sunday against any punitive measures as its stock market tumbled, with the fallout from the crisis threatening to imperil Crown Prince Mohammed bin Salman's much-hyped economic reform drive.

Following Riyadh's assertion it would retaliate, Britain, France and Germany released a joint statement saying they were treating Khashoggi's disappearance "with the utmost seriousness".

Khashoggi, who vocal critic of Prince Mohammed, vanished after entering the consulate on October 2.

Saudi Arabia insists Khashoggi left the building safely and dismissed accusations that authorities had ordered his murder by a hit squad as "lies and baseless allegations".

Turkish officials have said they believe Khashoggi was killed inside the mission and claims have been leaked to media that he was tortured and even dismembered.