Russia is the most active foreign adversary trying to influence the Nov. 5 U.S. presidential election, while China is more focused on influencing down-ballot races, a senior U.S. intelligence official said on Friday. The official said Iran is more active than in past cycles, stepping up its efforts to sway voters leading up to the presidential and congressional election. The U.S. intelligence community is increasing the use of private warnings to targets of foreign influence operations, the official added in a briefing to reporters. The briefing followed U.S. money-laundering charges against t…