The United States on Friday called on eastern Libyan commander Khalifa Haftar to stop his offensive on the capital held by the internationally recognized government and warned against Russian interference. Haftar’s Libyan National Army (LNA) has been trying since April to take Tripoli, part of a power struggle in the oil producing nation since the overthrow of Muammar Gaddafi in 2011. The LNA denies it has foreign backing.