TRIPOLI (Reuters) - Libya’s internationally recognised Government of National Accord (GNA) has detained Abdalrahman al-Milad, a coastguard commander sanctioned by the United Nations for alleged human trafficking and migrant smuggling, its interior ministry said on Wednesday. The ministry said it had detained Milad at the request of the U.N. Security Council and that it had referred the case to the public prosecutor to take legal measures against him. Milad heads a coastguard unit in Zawiya, just west of Tripoli, and was one of six people sanctioned by the U.N. for involvement in people trafficking or smuggling in Libya two years ago. Migrants had testified that they had been taken to a detention centre on one of the ships used by Milad and were then held in brutal conditions and beaten. He denied any wrongdoing or involvement in smuggling in a phone call to Reuters in 2018. Smugglers have been able to make vast profits by exploiting a security vacuum in Libya since the 2011 NATO-backed uprising that toppled Muammar Gaddafi and left many state institutions under the control of armed groups. Libya has been divided since 2014 between the GNA in Tripoli and the eastern-based Libyan National Army (LNA) of Khalifa Haftar. There are more than half a million migrants in Libya, a major launching point for journeys across the Mediterranean to Europe, according to the U.N., which says it is not a safe port for migrants to be returned to. On Saturday, the medical charity Doctors Without Borders said 60 migrants were being held in captivity by an armed group in Sabratah in western Libya.