In a statement released on Thursday, the Qatari Foreign Ministry called for the immediate release of Mohsen Saleh Saadoun al-Qurabi, 63, who was taken into Saudi custody last month while returning from Yemen.
"The arrest and detention of the Qatari citizen al-Qurabi by the Saudi authorities as he was returning from Yemen on April 21, where he visited his family and without committing any wrongdoing and without any charge, is a flagrant violation of national laws," the statement read.
It also noted that the Qatari national suffered from "chronic health problems that require continuous health care."
Additionally on Thursday, Qatar’s National Human Rights Committee (NHRC) strongly condemned Qurabi's "arbitrary detention" by the Saudi-led coalition that has been leading a deadly military campaign against Yemen since March 2015, Presstv reported.
The committee further urged international human rights organizations to intervene and secure the Qatari citizen's release, complaining that he had been denied contact with his family and a lawyer.
Qurabi's arrest is a "continuation of the series of human rights violations by the blockade countries against the state of Qatar and its citizens," the NHRC said.
It also held the Saudi authorities fully responsible for Qurabi's safety, warning that he risked "torture and other ill-treatment in violation of international conventions related to human rights."
Saudi-owned Al Arabiya TV reported that Qurabi had been arrested as he attempted to cross from Yemen into Oman. The channel further claimed that the Qatari national was an intelligence officer suspected of supporting Yemen's Houthi Ansarullah movement.
Last June, Saudi Arabia, Egypt, Bahrain, and the UAE imposed a land, naval and air blockade on import-dependent Qatar, accusing Doha of supporting terrorism, an allegation strongly denied by Doha.
The Saudi-led quartet presented Qatar with a list of steep demands and gave it an ultimatum to comply with them or face consequences.
Doha, however, refused to meet the demands and stressed that it would not abandon its independent foreign policy.