LONDON—World stocks slid, oil prices jumped and the rouble tanked to fresh record lows on Monday, as the West ramped up sanctions against Russia for its attack on Ukraine that included blocking banks from the SWIFT global payments system. Russia’s central bank raised its key interest rate to 20 percent from 9.5 percent in an emergency move, and authorities told export-focused companies to be ready to sell foreign currency as the rouble slid almost 30 percent to record lows versus the dollar. As an economic crisis loomed in Russia, the fallout of tougher sanctions from the West imposed over the weekend rippled out across financial markets. European stocks slumped 2 percent. European banks most exposed to Russia, including Austria’s Raiffeisen Bank, UniCredit, and Societe Generale, dropped between 9 and 15 percent, while the wider eurozone banking index fell 7 percent. U.S. stock futures were deep in negative territory, although MSCI’s …