By Matt Scuffham, Sinead Cruise and Niket Nishant NEW YORK/LONDON (Reuters) – Goldman Sachs Group Inc said on Thursday it was closing its Russian business, becoming the first major U.S. bank to exit following Russia’s invasion of Ukraine and putting pressure on rivals to follow. Operating in Russia has become increasingly difficult for Western financial institutions amid international sanctions against that country, and banks have been debating whether to remain. While European banks are the most highly exposed to Russia, U.S. banks still have significant exposure, totaling $14.7 billion, acco…