(Refiles to insert Global Markets tag in headline) By Pete Schroeder WASHINGTON (Reuters) – The selloff on Wall Street worsened Monday and oil prices turned lower as rising geopolitical tensions and the Fed’s plans to reduce economic stimulus took their toll on investors. Jitters over the prospect of a Russian attack on Ukraine and anticipated Fed tightening following its Wednesday meeting kicked a January stock selloff into overdrive. The Nasdaq Composite was down over 3% in midday trading, while the Dow Jones Industrial Average and S&P 500 were down 2.5% and 2.9%, respectively. The S&P was o…