.Wall Street stocks tumbled on Friday after US President Donald Trump threatened "massive" tariffs on China, sparking renewed trade war concerns following months of improving relations between the two countries. All three major US indices finished sharply lower, with the broad-based S&P 500 down 2.7 percent at 6,552.51. The Dow Jones Industrial Average dropped 1.9 percent to 45,479.60, while the tech-heavy Nasdaq Composite Index sank 3.6 percent to 22,204.43. The sell-off reflects investor fears that the threatened tariffs could escalate tensions between the US and China, reversing the recent positive trend in trade relations.