Volia, one of Ukraine's biggest telecommunication providers, has said it is experiencing an internal attack on its network. Efforts are under way to restore full service by 2300 Kyiv time, the company has said in a statement.
"Disruptions to the Internet access in Kyiv started at 1740. We are doing our utmost to restore services," the company said.
According to social media users, Volia customers experienced connectivity problems all over Ukraine.
Later the company said an external attack on its network caused Internet outage in Kyiv and made the call centre and corporate website of the company inaccessible.
Volia is Ukraine's third biggest Internet provider after Ukrtelecom and Kyivstar. It has over 600,000 customers in around 30 cities of Ukraine.