Republican officials have accused Ukrainian leader Vladimir Zelensky of interfering in US electoral politics and "campaigning" for presidential candidate Kamala Harris, after he visited an arms factory in the crucial swing state of Pennsylvania.The Ukrainian leader was flown into Pennsylvania in a US Air Force C-17 military aircraft and was provided with Secret Service protection, both of which were paid for with US taxpayer money, the GOP lawmakers said in a letter to Pentagon Inspector General Robert Storch on Tuesday.