[...] But authorities said they did not know the motive. Late Friday night Norwegian broadcaster TV2 said the man arrested was Anders Behring Breivik, a 32-year-old Oslo resident, although a police spokesman wouldn't confirm that.
A Facebook page matching that name and description gave the man's beliefs as "Christian" and "conservative" and said he runs a farm.
A police official suggested to the Associated Press that the incident was homegrown, saying it was more akin to "Oklahoma City" than "World Trade Center," the news agency reported.
Both strikes Friday targeted Norway's ruling Labor Party. The first incident, at about 3:30 p.m., involved at least one bomb blast in central Oslo that damaged a number of government buildings including the finance ministry and the government headquarters. At least seven people were killed.
That was followed later in the afternoon by an attack at the island of Utoya about 20 miles away, where a man dressed as a police officer opened fire, shooting several people attending the summer camp of the youth wing of the Labor Party. Police didn't give ages for the dead. The camp caters to youths from 13 to 20 years olds.
Acting police Chief Sveinung Sponheim said that police found undetonated explosives at the camp site. [...]