LONDON (AP) — Ukraine was repeatedly attacked by sophisticated cyberspies as tensions between pro-Russian and Western-leaning factions escalated in recent months, according to a report from U.K.-based defense contractor BAE Systems.

Ukrainian computer systems have been targeted by at least 22 attacks launched by “committed and well-funded professionals” since January 2013, BAE found. While BAE didn’t identify the source of the attacks, a German company said the espionage software has “Russian roots.”