WASHINGTON — An influential British think tank and Ukraine’s military are disputing a report that the U.S. cybersecurity firm CrowdStrike has used to buttress its claims of Russian hacking in the presidential election. The CrowdStrike report, released in December, asserted that Russians hacked into a Ukrainian artillery app, resulting in heavy losses of howitzers in Ukraine’s war with Russian-backed separatists. But the International Institute for Strategic Studies (IISS) told VOA that CrowdStrike erroneously used IISS data as proof of the intrusion. IISS disavowed any connection to the CrowdStrike report. Ukraine’s Ministry of Defense also has claimed combat losses and hacking...