Lower Saxony state's interior minister, Boris Pistorius, condemned the attack Thursday. Police said the 26-year-old suspect, who has been detained, appeared to have badly injured his hand when the explosives detonated early. Officers seized evidence, including weapons, at his home.
Authorities say the suspect is linked to the far-right scene. The 41-year-old woman who was targeted had been active in so-called Antifa campaigns against neo-Nazis. Left-wing groups are planning a protest Friday following the attack.
German authorities have warned of the growing threat of far-right extremism. Next week sees the start of the trial against two men suspected of involvement in the killing of Walter Luebcke, a member of Chancellor Angela Merkel's party who was gunned down outside his home last year.
One of the suspects in the Luebcke case has a long history of neo-Nazi violence.