Thieves snatched priceless treasures belonging to the Swedish crown jewels on Tuesday night in a daring raid on a cathedral, before fleeing and escaping by motorboat.

Their haul included two royal crowns of King Karl IX and Queen Kristina, as well as an orb.

Police said there had not yet been any arrests following the theft from Strängnäs Cathedral in southeastern Sweden, where the items were on public display.

A witness told Aftonbladet, a Swedish evening newspaper: "One of my friends saw two people running. I saw the boat just there, a white little boat, with a motor on the back.

"The two men hurriedly jumped on board. We contacted the police and they told us they had taken something from the Cathedral."

The police hunt included helicopters and motorboats, according to Thomas Agnevik, a spokesman for the police, who said the lost jewels were priceless.