Three men with ties to the Swedish neo-Nazi movement were sentenced on Friday to up to eight and a half years in prison for bomb attacks in western Sweden over the past year.

Viktor Melin, 23, received the longest sentence for carrying out bomb attacks on a left-wing bookstore and an asylum center and an attempted bombing of a second asylum center.

The attacks took place in November and January. Nobody was killed but one man was seriously wounded in the asylum center attack.

A 50-year old man, Jimmy Jonasson, was sentenced to five years in prison for assisting in two of the attacks and a 23-year old man, Anton Thulin, got one year and six months for assisting in the attempted bombing.

"All three defendants have a common background in the Nordic Resistance Movement and have gotten to know each other through the movement's activities," said a district court in Sweden's second largest city, Gothenburg.

The Nordic Resistance Movement, founded in 1997, is described as the most violent Nazi organization in Sweden, by to the Swedish anti-racism magazine Expo.

Sweden, which took in the highest number of refugees per capita in Europe in 2015, saw dozens of arson attacks against refugee centers that same year. The culprits have rarely been caught.

"The defendants have realized that their actions posed danger to people's lives and health," the Gothenburg court said, adding DNA traces from the 23-year-old were found on the bombs.

The Swedish intelligence service Sapo estimates that hundreds of violent extremists in Sweden come from far-right movements.

The Nordic Resistance Movement has nearly 200 active members, according to Expo.