Sweden has told its citizens to be ready to live off-grid for a week in case of a military attack.
Russia’s bombardment of Ukrainian cities is a warning of what could happen, Sweden's new civil defence chief said.
It comes with Sweden toughening its security stance and seeking to join Nato in light of Russia’s aggression.
A new government recently appointed Sweden’s first civil defence minister since 1945, an MP called Carl-Oskar Bohlin.
Mr Bohlin suggested people should buy torches, headlamps, matches, batteries, candles, cans and sleeping bags to prepare for a crisis.
Russia’s “brutal warfare” in Ukraine showed that civilian infrastructure could be targeted and civil defence should be adjusted accordingly, he said.
“Prepare to be able to get by without the help of society for a week, but preferably longer,” Mr Bohlin wrote in an article published on the government’s website.
“If we can handle an armed attack, we will also be able to handle a crisis, such as a natural disaster or power outage.”
Ukraine says millions of people have been left without power by Russian bombardment in recent weeks.
Attempts to rebuild damaged infrastructure have been hampered by continued drone and missile strikes.
Ukraine conflict — in pictures
Western officials say Moscow is trying to freeze Ukraine into submission after a series of battlefield setbacks for Russian troops.
Ukraine’s allies have donated equipment including power generators and sleeping bags to help it withstand winter.
They have also put an increasing focus on resilience at home as the threat of armed conflict comes back into view in Europe.
Although many civil defence plans were scrapped after the end of the Cold War, some are now being revived.
Mr Bohlin said he was asking for almost a billion Swedish kronor ($95.6 million) to improve civil defence in Sweden.
But he invited citizens to make it a New Year’s resolution to strengthen their own preparedness at home.
Germany’s interior minister recently announced plans to hold a nationwide “day of civil defence” in 2023.