An international human rights group on Sunday accused the United Arab Emirates of secretly arresting 10 Libyan citizens and six Emiratis in August and September and called on authorities in Abu Dhabi to reveal their whereabouts.
The UAE made no official comment on the report but a source familiar with legal procedures in the country said the individuals were being held in connection with financing terrorism and facilitating arms shipments to militants.
Human Rights Watch (HRW) said in a statement the circumstances surrounding the detentions appeared consistent with previous cases in which authorities had detained Emirati citizens associated with a local Islamist group and foreign nationals with alleged ties to the Muslim Brotherhood.
"The new disappearances are evidence of the UAE's increasingly repressive behaviour," said Joe Stork, deputy Middle East and North Africa director at HRW.
The UAE, a US ally in its fight against militants in Syria and Iraq, has cracked down on Islamists, accusing members of the local Islah group of plotting to seize power and last year jailing 69 of them after a trial that was condemned by human rights organisations.
"These individuals have been detained in relation to financing extremism and terrorism and facilitating the transfer of fighting equipment," a source familiar with legal proceedings in the UAE said.
He said they were being questioned and then would be charged and put on trial.
HRW quoted relatives of two of the detained Libyans, brothers Mohamed and Salim Elaradi, who have lived in the UAE since the 1990s, as saying that neither man had made any contact with their families since security forces detained them on Aug. 28.
"The family members said that the authorities refuse to acknowledge that the men are in custody or divulge their whereabouts," it said.
The pair are brothers of Abdulrazag Elaradi, a member of the Muslim Brotherhood-affiliated Justice and Construction Party in Libya, but their families say they have no political affiliations, HRW said.
HRW said the Libyan ambassador had confirmed the detention of the two and two other brothers, Kamal and Mohamed Kamal Eldarat.
HRW said it had also contacted relatives of another three of the 10 Libyans it says have been detained in the UAE since the last week of August, all of them businessmen.
During a visit to Abu Dhabi last month, Libyan Prime Minister Abdullah al-Thinni said that the UAE had arrested seven Libyan nationals.
The six detained Emiratis were taken into custody on Sept. 22 in the town of Khor Fhakkan in the Emirate of Sharjah, HRW said, quoting a source close to one of their families. HRW said the detained Emiratis included a 17-year-old youth identified as Omar Ibrahim Mahmood.