By Caroline Valetkevitch NEW YORK (Reuters) – The Nasdaq sharply extended gains and the S&P 500 cut its losses briefly in Thursday afternoon trading as U.S. President Joe Biden said Russia’s military attack on Ukraine is unfolding largely as U.S. officials had predicted. Biden said he is authorizing new sanctions against Russia, including exports. The Dow Jones Industrial Average fell 566.21 points, or 1.71%, to 32,565.55, the S&P 500 lost 28.4 points, or 0.67%, to 4,197.1 and the Nasdaq Composite added 86.67 points, or 0.66%, to 13,124.16. The Nasdaq was up more than 1% following Biden’s comm…