WASHINGTON—The United States and Germany said Wednesday that Russia’s military buildup near Ukraine’s border poses an “immediate and urgent challenge” to European security and that any intervention will draw severe consequences. But the country’s top diplomats left open what those consequences would be and how differences on arming Ukraine and a controversial Russian gas pipeline will be resolved. Secretary of State Antony Blinken and German Foreign Minister Annalena Baerbock sought to present a unified front on Russia after a meeting in Washington. “Both Germany and the United States see Russia’s actions toward Ukraine as an immediate and urgent challenge to peace and stability in Europe,” Blinken said. “We condemn Russia’s military buildup on Ukraine’s borders, as well as Russia’s increasingly harsh rhetoric as it continues to push the false narrative that Ukraine seeks to provoke (Russia),” he said. “That’s a little bit like the fox saying it had no choice …