The Ukrainian natural gas company that prompted President Donald Trump to seek investigations from Ukraine's president over its hiring of former Vice President Joe Biden's son was hacked by Russian spies, security experts said in a report released Monday.

Burisma Holdings, founded by Mykola Zlochevsky.

The Main Intelligence Directorate of the General Staff of the Russian Army, or GRU, "launched a phishing campaign targeting Burisma Holdings" as early as November, according to the cybersecurity firm Area 1 Security.