GOTEBORG, Sweden — The Swedish authorities on Wednesday were investigating the burning of more than 100 vehicles on the nation’s west coast, in what they said was a coordinated arson attack by groups of young men.

The attack began shortly after 9 p.m. Monday, when several cars were reported to be on fire in the main square of Vastra Frolunda, a suburb of Goteborg, Sweden’s second-largest city.

By the time those blazes were over, “33 cars had been lit on fire and about 50 cars had been damaged,” Thomas Fuxborg, a spokesman for the Swedish Police, said in a phone interview.

A few minutes after the fires broke out in Vastra Frolunda, there were reports of cars on fire in Hjallbo, a district in northeast Goteborg. Fires were also reported in Kronogarden, a district of Trollhattan, about 45 miles north of Goteborg, the police said.