OPEC and its allies are working towards a deal to reduce oil output by at least 1.3 million barrels per day, four sources said, adding that Russia’s resistance to a significant production cut was so far the main stumbling block.  OPEC meets on Thursday in Vienna, followed by talks with allies such as Russia on Friday, amid a drop in crude prices caused by global economic weakness and concerns about an oil glut due largely to a rise in U.S. production. The producer group’s de facto leader, Saudi Arabia, has indicated a need for steep reductions in output from January but has come under pressure from U.S. President Donald Trump to help support the world economy with lower oil prices. Possibly complicating […]