BRUSSELS - Russia conducted a "continued and sustained" disinformation campaign against Europe's recent parliamentary elections, the European Union reported Friday, the latest sign that Russia's high-tech efforts to influence democratic votes have not slowed down.

The report found that Russia sought to influence voter behavior and, in some cases, suppress turnout. These conclusions echo the conclusions of official U.S. investigations into the 2016 presidential election, which reported that Russians sought to damage Democrat Hillary Clinton and help elect her rival, Republican Donald Trump, while also working to undermine democratic institutions in the United States.

Friday's European Union report said the Russian interference in parliamentary campaigns "covered a broad range of topics, ranging from challenging the Union's democratic legitimacy to exploiting divisive public debates on issues such as of migration and sovereignty...There was a consistent trend of malicious actors using disinformation to promote extreme views and polarize local debates, including through unfounded attacks on the EU."

The report said major U.S. technology companies, including Google, Twitter and Facebook, had taken steps to combat Russian disinformation, but the report also said, "more needs to be done by the platforms to effectively tackle disinformation."

European officials had been fearful that the Kremlin would put the May elections for European Parliament in its crosshairs. The legislature has given a foothold to far-right, pro-Russian lawmakers in past years, and pro-EU policymakers thought that Russia might use the recent voting to try to crack open the system.

The parliamentary elections, which in this case ran from May 23 until May 26, are the one occasion every five years that Europe's 500 million citizens have a chance to pick representatives to a common legislative body. It is the world's largest exercise of democracy outside India but often is marred by low turnout.

This year, far-right anti-EU forces won a record result, capturing about a quarter of the European Parliament's seats. But it was only a modest boost over their previous share, despite repeated terrorist attacks, a refugee crisis and a wave of far-right leaders expanding power inside national legislatures. These right-wing movements fell short of expectations in the vote.

Security officials, diplomats and candidates said that their worst fears about Russia did not come to pass. There were no known high-profile hacking efforts, such as that of the Democratic National Committee during the 2016 U.S. presidential campaign. Nor did there appear to be efforts to damage individual candidates, as happened in 2017, when then-candidate Emmanuel Macron's campaign emails were published online two days before he was elected president of France.

But a top EU security official said Friday that there was nevertheless an ongoing and significant Russian effort to target Europeans with disinformation on a daily basis.

"The trend as far as we can see is that rather than trying to do big-scale hacking leaks, it is to have a customized, carefully targeted approach that uses in particular fake accounts and bots to accelerate and amplify divisive content that is already out there," said EU Commissioner for Security Union Julian King.

And he said that an EU group charged with tracking foreign disinformation found double the number of misleading items originating from Russia in the months leading up to the election compared to the same period a year ago.

King and other top EU officials said that they would not rule out additional regulation of social networks and platforms such as YouTube, which is owned by Google, to try to combat disinformation. Efforts until now have been voluntary. King said that a Facebook effort to promote transparency about who was purchasing political advertising was only partially successful, since many political ads were not properly identified by the network's automated systems.

The EU report said that Russian-backed outlets latched on to the April fire that destroyed part of the roof and spire of Paris' Notre Dame cathedral as a way to push the idea that Western and Christian values are in decline in the European Union. Russian outlets also blamed a leaked video that led to the fall of Austria's government on "a European deep state," the report said.

Oxford University's Internet Institute found in a report shortly before the vote that there was sharp variation in terms of the vulnerability of European nations to disinformation. Western European nations such as France and Germany, with strong cultures of independent journalism and governments actively fighting disinformation, resisted phony news stories well. But other nations, such as Poland and Hungary, where news organizations are closely aligned with political and economic elites, are more vulnerable to disinformation, the Oxford group found.

"I worry about a vicious cycle in that voters who don't have high-quality news elect poor quality politicians," who in turn may spread misleading information, said Philip N. Howard, co-author of the Oxford report.

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Timberg reported from Washington. The Washington Post's Quentin Ariès in Brussels contributed to this report.