Washington, Sep 6 (IANS) Russia has dismissed US concerns about an alleged Russian military build-up in Syria which US Secretary of State John Kerry said could lead to escalation of the conflict in the war-torn country. Kerry made his views k**wn to his Russian counterpart Sergei Lavrov during a telephone conversation on Saturday, after President Vladimir Putin denied Russia's involvement in military operations against the Islamic State (IS) group in Syria, reported Xinhua.