nizhnebureisky russia new u.s. sanction impose russia negative consequences unite state backfire u.s. energy major igor sechin chief executive officer russia large oil producer rosneft say thursday u.s. president donald trump grudgingly sign law new sanction russia wednesday move moscow say amount full-scale trade war end hop good tie trump administration sanction begin backfire introduce positive sechin tell reporters power u.s. president limit sometimes seem sanction impose us sechin say situation saw positive consequences rosneft negative consequences say u.s. sanction start work american partner positive ones learn next four weeks say without elaborate rosneft ceo u.s. sanction backfire hurt u.s. energy major