The unit also is known for posing as a CyberCaliphate hacking outfit "supporting the Islamic State."

Unit 54777, or the 72nd Special Service Center, is the center of the Russian military’s psychological-warfare capability, say Western intelligence officials.

“They are the center of gravity for Russian psychological operations,” an officer from a Western intelligence agency told The Washington Post. “Their hand has been seen in many of the most well-known campaigns."

Last month, when the Russian border guard fired upon and seized three Ukrainian ships in the Black Sea, young men in a Ukrainian border region were sent text messages to report for military service.

The text messages, the agency said, were sent by the psy-ops.

Unit 54777 has several front organizations that are financed through government grants as public diplomacy organizations but are covertly run by the GRU and aimed at Russian expatriates, the intelligence officer said. Two of the most significant are InfoRos and the Institute of the Russian Diaspora. In February 2014, for instance, shortly before Russia annexed Crimea from Ukraine, the institute and InfoRos launched an appeal, purportedly on behalf of Russian organizations in Ukraine, calling on Putin to intervene in the brewing crisis, the intelligence officer said.

The appeal was intended to convince the international community as well as the Russian public that Ukraine was not unified and to increase pressure on the anti-Russian protesters in Kyiv, the intelligence officer said.

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Unit 54777 also is thought by Western intelligence to work with other psy-ops and cyber units, such as the CyberCaliphate, a hacking outfit passing itself off as supporters of the Islamic State but really part of the same GRU unit that would penetrate the Democrats’ networks in 2016.

The CyberCaliphate hijacked the U.S. Central Command’s Twitter feed in January 2015 and targeted military spouses, hacking their Twitter accounts and posting threats.

In April 2015, the CyberCaliphate, again claiming to be Islamic State supporters, took France’s TV5Monde off the air for 18 hours.

“What the GRU demonstrate very consistently is profound innovation with available resources,” said Joe Cheravitch, a Russia analyst with Rand Corp., a nonprofit, federally funded research institute. “That’s what really makes them dangerous.”

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In many ways, the Ukraine conflict provided the test bed for the GRU’s information and cyberwarfare operations, analysts say.

Spies directed by Unit 54777 created fake personas and posted comments on Russian and English-language social media platforms, as well as on articles in Western publications, according to the Western intelligence agency. Often, they sought to stoke divisions between pro-Russian and pro-Western Ukrainians by portraying themselves as Ukrainian “patriots” fed up with the pro-Moscow “Nazis” and “fascists” who they blamed for the violence.

In December 2015, GRU hackers plunged some 225,000 people into darkness after gaining access to Ukraine’s power grid, according to U.S. intelligence and private-sector analysts. It was the first known cyberattack to result in a power outage.

GRU units also are suspected of deploying a highly disruptive computer virus dubbed NotPetya, analysts said. Launched on June 28, 2017 — Ukraine’s Constitution Day — the virus wiped data from the computers of banks, energy firms, senior government officials and an airport in Ukraine.

“Ukraine is to 21st-century hybrid warfare what Spain was in the 1930s for battlefield blitzkrieg techniques — the place where the bad guys try out what they may use against us later on,” said Daniel Fried, a former senior State Department official who helped lead the West’s response to Moscow’s aggression against Ukraine.