Russian hackers were inside Ukrainian telecoms giant Kyivstar's system from at least May last year in a cyberattack that should serve as a 'big warning' to the West, Ukraine's cyber spy chief told Reuters. Keep up with the latest news from around the world: https://www.reuters.com/ #News #Reuters #newsfeed #world #Ukraine #technology #UkraineRussiaWar #telecoms #Kyivstar #Russia #hackers Subscribe: http://smarturl.it/reuterssubscribe Reuters brings you the latest business, finance and breaking news video from around the globe. Our reputation for accuracy and impartiality is unparalleled. Get the latest news on: https://www.reuters.com/ Follow Reuters on Facebook: https://www.facebook.com/Reuters Follow Reuters on Twitter: https://twitter.com/Reuters Follow Reuters on Instagram: https://www.instagram.com/reuters/?hl=en