WASHINGTON—U.S. Secretary of State Antony Blinken on Friday accused Russia of “gaslighting” and pushing a “false narrative” that it was under threat from Ukraine and NATO to justify a troop build-up near its border with the former Soviet republic. Blinken addressed reporters at the State Department ahead of meetings of U.S. and Russian diplomats in Europe next week aimed at bringing down the temperature between Russia and the West, and after a virtual meeting with NATO foreign ministers earlier on Friday. Blinken said Russia has worked for years to undermine Ukraine’s democratic institutions, interfere in its politics, block energy and commerce, and sow mistrust with propaganda and disinformation. Russia had positioned nearly 100,000 troops near its border with Ukraine “with plans to mobilize twice that number on very short order” and justified doing so with “misinformation” that Ukraine was seeking to provoke a conflict, Blinken said. “That’s like the fox …