Libya’s National Oil Corporation says production has been suspended at the vast Al-Sharara and Al-Fil fields since gunmen cut off their pipelines.

Stephanie Williams, UN chief Antonio Guterres’s special adviser on Libya, said she has been following the reports with concern. She said blocking oil production deprives all Libyans of their major source of revenue and the blockade should be lifted immediately.

Libya has undergone a decade of chaos since the 2011 uprising that overthrew and killed Moammar Kadhafi. Oil installations have often been attacked or blockaded by armed groups seeking to extract concessions such as jobs or a larger share of revenues.