BANGKOK—Oil prices surged nearly 5 percent and stock prices dropped after Russian President Vladimir Putin ordered forces into separatist regions of eastern Ukraine, bringing a long-feared invasion a step closer. Russia is a major energy producer and the tensions over Ukraine have brought wide swings in volatile energy prices, on top of the inevitable risks of a broader conflict. Oil prices already had surged recently to their highest level since 2014. By early Tuesday, the advance of U.S. benchmark crude oil had abated slightly. It was up $3.66, or 4.1 percent, at $93.87 per barrel in electronic trading on the New York Mercantile Exchange. The price of Brent crude, the standard for international oils, gained $2.71, or 2.9 percent, to $98.10 per barrel. U.S. trading was closed Monday for Presidents Day, but markets in Europe and Asia shuddered as Putin moved to secure Russia’s hold on Ukraine’s rebel regions, adding …