U.S. National Security Adviser John Bolton adjusts glasses during a news conference in Moscow, Russia October 23, 2018. REUTERS/Maxim Shemetov

MOSCOW (Reuters) - U.S. national security advisor John Bolton said Russian meddling in U.S. elections had backfired on Moscow, providing a lesson to the Kremlin: “Don’t mess with American elections.”

Speaking on a visit to Moscow, Bolton said there was no evidence the meddling -- which Russia has denied -- materially affected the outcome of the 2016 presidential election, but that it did create mistrust toward Russia.