An Islamist militant group says it is holding a Romanian man kidnapped from a mine in Burkina Faso last month, Mauritania's Alakhbar news website said late on Monday. A speaker claiming to represent one of the most dangerous groups in the Sahara, Al-Mourabitoun, said it had offered terms to Romania for his release. "The Romanian government will be entirely responsible for the fate of the hostage if it does not take the opportunity given to free its citizen," said Adnan Abu Waleed al-Sahrawi, without giving details. The Romanian security officer, named by local media as Iulian Ghergut, was seized from the Tambao manganese mining project in northern Burkina Faso on April 4. The mine is operated by Pan African Minerals, a subsidiary of Romanian-Australian businessman Frank Timis's Timis Corporation, and is near the border with Mali's turbulent north. "Competent Romanian authorities, represented in the inter-institutional crisis cell created by the foreign ministry after the abduction, are urgently verifying the information presented in the news, including the audio message," the Romanian foreign ministry said in a statement released on Tuesday. Al-Mourabitoun was established in 2013 by uniting fighters loyal to Mokhtar Belmokhtar, one of the Sahara's best known jihadists, and MUJWA, an Islamist group operating in West Africa that was headed by Sahrawi. A medley of Islamists, including MUJWA as well as Belmokhtar's fighters, took control of northern Mali in 2012 but were scattered when French troops arrived. However, isolated attacks continue against local and foreign targets. Monday's statement reiterated an earlier pledge of allegiance to Islamic state, although Belmokhtar has rejected this pledge, suggesting a rift may be emerging in the group.