The Manhattan apartment and Southampton mansion of a Russian oligarch with close ties to President Vladimir Putin were raided by federal agents on Thursday, according to the FBI and a report. An FBI spokesperson confirmed agents “conducted law enforcement activity” at the Upper East Side high-rise and Long Island estate linked to billionaire Viktor Vekselberg, but declined to comment further. FBI officials and Homeland Security Investigation agents were seen carrying boxes out of Vekselberg’s 515 Park Ave. apartment building and his Southampton mansion at 19 Duck Pond Lane, according to NBC New York, which first reported the searches. The US...