PARIS (AFP) - Kristian Vikernes, the Norwegian far-right metal musician arrested in France over fears of a "major terrorist act", is a "survivalist" who was actively preparing for an emergency, his lawyer said.

The 40-year-old, who once served 16 years in jail for stabbing to death a fellow musician, was arrested on Tuesday in the central Correze region along with his wife Marie Ms Cachet, 25.

Vikernes, who also goes by the name "Varg", Norwegian for "wolf", remained in custody on Thursday but Ms Cachet was released a day earlier, a judicial source told AFP.

On Wednesday, Vikernes' lawyer Julien Freyssinet said that the Norwegian was far from preparing a terror act, describing him as a "survivalist".

Survivalism is a movement of people who actively prepare for emergencies - by for instance stockpiling food, water and medicine or building protective structures - and sometimes believe a social, political or natural catastrophe is imminent.

"We must put this case into perspective," Mr Freyssinet told reporters.

He said weapons seized by officers at the couple's home had been acquired "completely legally and without hiding a thing, as part of a philosophy followed by the couple - that of survivalism". The Interior Ministry said at the time of the arrest that Vikernes was "close to the neo-Nazi movement" and could have been preparing a "major terrorist act".

However Interior Minister Manuel Valls later conceded no specific target or project had been identified, but the authorities had decided to "act before and not afterwards". Officers seized five long-range weapons at the couple's home, including four 22-calibre Long Rifles.

They were also concerned about the antisemitic and xenophobic messages that Vikernes posted online.

Under French anti-terrorism laws, suspects can be held for up to 96 hours, which means Vikernes may remain in custody until Saturday morning.

The Norwegian is a notorious black metal musician in his country, known for the deadly stabbing as well as accusations of setting fire to one or more churches in the early 1990s.

Musicians and fans of black metal - an extreme subgenre of heavy metal - often express anti-Christian views and were involved in the burning of more than 50 churches in Norway between 1992 and 1996.

After serving 16 of his 21 years in jail, Vikernes moved to France where he settled with Ms Cachet and their three children.