Updated

Three men with links to a right-wing extremist group have been charged with attempted murder and endangering the public in connection with recent attacks in southern Sweden targeting newly arrived migrants and a left-wing group, Swedish authorities said Friday.

Prosecutor Mats Ljungqvist tied the men to an unexploded device found Jan. 25 near a campsite accommodating migrants, as well as to a Jan. 5 bomb that seriously injured one person, and a November 2016 blast outside a left-wing group's offices in Sweden's second largest city, Goteborg.

A construction error meant the campsite device never went off, he said in a statement. He didn't elaborate.

Ljungqvist said the men seemed to be "dissatisfied with the leadership" of the white-supremacist Nordic Resistance Movement for not using violent means to achieve their ends. Two of the men, whom he didn't name, had received military training in Russia before the attacks.

According to Ljungqvist, the acts were not linked to the Nordic Resistance Movement, hinting the men acted on their own.

The Swedish security service SAPO has been part of the investigation that led to the arrests of the men in February and March.

The suspects have "an ideological link to individuals followed by the Security Police in the context of our mission," the agency said in a statement.

Their three-day trial is scheduled to start June 21.