A warning to Swedes from two top defence officials to prepare for war has prompted concern and accusations of alarmism.

Civil Defence Minister Carl-Oskar Bohlin told a defence conference "there could be war in Sweden".

His message was then backed up by military commander-in-chief Gen Micael Byden, who said all Swedes should prepare mentally for the possibility.

However, opposition politicians have objected to the tone of the warnings.

Ex-prime minister Magdalena Andersson told Swedish TV that while the security situation was serious, "it is not as if war is just outside the door."

Children's rights organisation Bris said that its national helpline did not usually receive calls about the possibility of war. But this week, it had seen an increase in worried calls from youngsters who had seen news reports or posts on TikTok talking about it.

"This was well prepared, it wasn't something blurted out," Bris spokeswoman Maja Dahl told the BBC. "They should have provided information meant for kids when they come out with this kind of information for grown-ups."

Despite the starkness of the messaging, the remarks from the civil defence minister and military chief are being seen as a wake-up call.

After more than two centuries of peace, Sweden is a few steps from joining the Nato defensive alliance, waiting for a green light from Turkey's parliament and then from Hungary.

The commander-in-chief said his remarks were nothing new.

He visited Ukraine's eastern front a month ago and Sweden is one of a group of countries training Ukrainian pilots. Stockholm is also said to be considering sending advanced Gripen fighter jets to Ukraine.

"My ambition with this is not to worry people; my ambition is to get more people to think about their own situation and their own responsibilities," Gen Byden later told Aftonbladet newspaper.

Finland has already joined Nato, and Russian officials have suggested it will be "the first to suffer" if tensions with Nato escalate.

Sweden's civil defence minister said his aim was not for people to lose sleep, but to gain awareness of what was really going on. He appealed to local authorities, emergency planners and individuals to respond.

"If there is one thing that keeps me awake at night, it is the feeling that things are moving too slowly," Mr Bohlin told the Society and Defence conference on Sunday.

Ukrainian President Volodymyr Zelensky called on Sweden during the conference to work with his country and others to manufacture weapons and "get stronger together".

Prime Minister Ulf Kristersson added that in 2024, Sweden would meet Nato's target of spending 2% of economic output (GDP) on military defence, doubling its spending since 2020.

Defence specialist Oscar Jonsson said the tone of the warnings from defence chiefs was something of a storm in a teacup and that 90% of what had been said arose from frustration that too little was being done to build civil and military defence.

"Time is limited and it was aimed at being a wake-up call for agencies, individuals and departments," he told the BBC.

"The Swedish armed forces are incredibly competent, but the scale is nowhere near. The latest defence bill says we should set up 3.5 brigades, whereas Ukraine had 28 when the war started."

Gen Byden's warning to prepare mentally for war comes hard on the heels of a warning a month ago from the head of Poland's National Security Bureau (BBN), Jacek Siewiera, who said that "to avoid war with Russia, countries on Nato's eastern flank should adopt a three-year time horizon to prepare for confrontation".

He said a German Council on Foreign Relations report suggesting Germany and Nato should prepare their armed forces to be able to fend off a Russian attack in six years was "too optimistic".

Oscar Jonsson, a specialist from the Swedish Defence University, said that while war was a possibility, it would require several factors to fall into place: Russia's war in Ukraine coming to an end, its military having the time to rebuild and rearm its fighting force and for Europe to lose US military support.

All of which were within the realms of possibility, he added.