American and Afghan authorities are investigating a possible case of friendly fire in the Badghis province in the western part of Afghanistan, a remote area with a high concentration of Taliban. A search team was hunting for two American paratroopers who had disappeared two days earlier when they were trying to recover airdropped supplies that landed in a river. Heavy fighting broke out Friday, and eight Afghans were killed and 17 wounded, as were five American soldiers. Afghanistan’s defense ministry says the casualties likely happened during a NATO air attack. American officials would only say that an investigation was under way. Airstrikes have worsened already tense relations between NATO and the Afghan government. On Saturday, Kabul pushed back against U.N. recommendations for eliminating corruption and the influence of warlords, saying they were an infringement on Afghan national sovereignty.