LONDON — Less than two weeks before pivotal elections for the European Parliament, a constellation of websites and social media accounts linked to Russia or far-right groups is spreading disinformation, encouraging discord and amplifying distrust in the centrist parties that have governed for decades.

European Union investigators, academics and advocacy groups say the new disinformation efforts share many of the same digital fingerprints or tactics used in previous Russian attacks, including the Kremlin’s interference in the 2016 U.S. presidential campaign.

Fringe political commentary sites in Italy, for instance, bear the same electronic signatures as pro-Kremlin websites, while a pair of German political groups share servers used by the Russian hackers who attacked the Democratic National Committee.

The activity offers fresh evidence that despite indictments, expulsions and recriminations, Russia remains undeterred in its campaign to widen political divisions and weaken Western institutions. Despite online policing efforts by American technology companies, it remains far easier to spread false information than to stop it.