KYIV, Ukraine—Ukraine’s top diplomat asked Thursday for stronger Western backing, saying “words of support aren’t enough” amid escalating tensions in the country’s east and a Russian troop buildup across the border. Ukrainian Foreign Minister Dmytro Kuleba, speaking after talks with his counterparts from Estonia, Latvia, and Lithuania, asked the Baltic nations to reach out to other European Union and NATO members about offering “practical assistance” to Kyiv. More than 14,000 people have died in seven years of fighting between Ukrainian forces and Russia-backed separatists that erupted after Russia’s 2014 annexation of Ukraine’s Crimean Peninsula. Efforts to reach a political settlement have stalled, and violations of a shaky truce have become increasingly frequent in recent weeks. Ukraine and the West also have sounded alarmed about the concentration of troops along Russia’s western border, a buildup that the United States and NATO have described as the largest since 2014. Russia has argued …