Internet services have been disrupted in the north-eastern Ukrainian city of Sumy and the western Ukrainian province of Vinnytsia.
The outages are the latest in a number of severe network disruptions caused by Russia's unprovoked invasion of the sovereign nation.
Sumy lost connectivity at 11:30am local time on March 14, according to the Internet Outage Detection and Analysis (IODA) project at Georgia Tech. The city has been under siege since 24 February, with Russian troops having occupied some segments of the city and shelling others.
The outage in the Vinnytsia Oblast is linked to disruptions to Internet Service Provider VinAsterisk's network. The company said that the outage was caused by a "hacker attack," but did not share details.
Hackers previously brought down Viasat’s satellite Internet network in and around Ukraine, in an attack that is now being investigated by Western intelligence agencies.
A cyber attack on ISP Triolan caused an outage lasting more than 12 hours last week, while Ukraine's national telecoms operator, Ukrtelecom, went down for 40m in a nationwide outage.