Estonian officials have caught dozens of anglers fishing through holes cut in the ice of frozen lakes, despite the start of the spring thaw.
Estonia prohibits fishing on lakes from a certain date each year, because of the danger of injury or death if anyone should fall through the thinning ice.
The cut-off this year fell yesterday, and rescue patrols have as usual found far too many keen anglers enjoying their hobby, oblivious to the risks they are running, Estonia's reports.
But this year the Rescue Board is flexing its muscles, warning fishermen that it will call in the police and border guards if they don't quit the ice. Refusal to comply can lead to fines.
The authorities are concerned at their failure to raise enough awareness of the dangers involved, as 43 people drowned in lakes last year alone - eight of them in the spring months of March to May.
One problem is that the ice cover can vary considerably across Estonia, so some areas may see an obvious thaw while lakes elsewhere appear deep frozen.
But Mikko Virkala of the Estonian Rescue Board told that ice conditions "can change at any moment", and had a particular warning for anglers - "no fish is worth losing your life for".
His warning was put even more bluntly by the Rescue Board's , which said "fishermen are prone to accidents because they assume their experience means nothing will happen to them".
Even strong swimmers find it difficult to scramble out of freezing water without special hand picks, as fit adults can lose consciousness in a matter of minutes.
This has prompted rescue services around the country to raise awareness by inviting the media to cover public drills on how to remain safe on the ice, how to save someone in trouble, and what to do if you fall in.