President Volodymyr Zelensky says Russia has widened its attacks to target Ukraine's data centres and internet providers, seeking to cause maximum disruption for ordinary people.
"All this affects people's ability to stay connected, study, work," he said.
On Friday a Russian drone hit a business centre in the capital Kyiv, killing four people and damaging a data centre. A separate attack killed a 14-year-old boy. Israel's foreign ministry said he was an Israeli citizen.
Russia confirmed it had targeted a data centre site, saying it was being used by Ukrainian military intelligence.
About 100,000 households in Kyiv and the region suffered internet outages on Wednesday due to strikes.
Some firms have already begun moving data from damaged servers to facilities abroad.
In the north-western city of Lutsk, electronic information boards at public transport stops were not working on Friday, officials said. The city council said this was "due to damage caused by a Russian attack on data centres in Kyiv".
In Friday's social media post, Zelensky wrote: "The Russians are constantly expanding their escalation operation: American and other businesses, data centres, internet providers – for Russia, all ordinary life is simply a target.
"It is important that the world responds to all of this and that Russia feels the response to its terror."
Late on Friday, Zelensky said "additional decisions" had been made at his meeting with Ukraine's top defence and security officials to protect the country's data centres and other critical communications facilities to ensure their continuous operation.
Ukraine's Foreign Minister Andrii Sybiha has said that Russia was seeking to disrupt the flow of "life-saving information" by targeting data centres.