One of the FBI's most wanted fugitives has been arrested in a rural area of northern Wales after spending more than 20 years on the run.
Daniel Andreas San Diego is wanted for bombings in the San Francisco area, and now faces extradition to the United States, officials said on Monday, local time.
The suspected animal rights extremist remains in custody after appearing in Westminster Magistrates' Court on Tuesday.
He was "detained in an operation supported by Terrorism Police and North Wales Police", the UK's National Crime Agency (NCA) said.
FBI director Christopher Wray said in a statement that San Diego's arrest highlights the the bureau's relentlessness.
"No matter how long it takes, the FBI will find you and hold you accountable," he said.
The NCA said it arrested San Diego at a property near woods in the Conwy area of Wales, a coastal town about 8,000 kilometres from San Francisco.
San Diego, 46, is charged with planting two bombs that exploded about an hour apart in the early morning of August 28, 2003, on the campus of a biotechnology company in Emeryville, California.
He is also accused of setting off another bomb with nails strapped to it at a nutritional products company in Pleasanton, California, a month later.
The bombings didn't injure anyone, but authorities said the bomb at the biotechnology company was intended to harm first responders.
A group called Revolutionary Cells-Animal Liberation Brigade claimed responsibility for the bombings, citing the companies' ties to Huntingdon Life Sciences.
The location was a target of animal rights extremists because of its work with experimental drugs and chemicals on animals.
In 2009, San Diego became the first person suspected of domestic terrorism to be added to the FBI's Most Wanted Terrorism list.
A reward of $US250,000 ($380,000) was offered for information leading to his arrest.
The FBI released these enhanced images to help track down alleged domestic terrorist Daniel Andreas San Diego. (AFP: FBI Handout)
Photos of him appeared on billboards from California to New York, including Times Square, the FBI said.
He also featured on the TV program America's Most Wanted several times.
San Diego grew up in an upper-middle class suburb of Marin County north of San Francisco.
He had worked as a computer network specialist, was a skilled sailor and was known to carry a handgun, the FBI said.
Back in 2003, the FBI had San Diego under surveillance when he parked his car near downtown San Francisco but he vanished into a transit station — not to be seen again.
Over the years, there had been numerous sightings reported and investigators announced searches in Massachusetts and Hawaii.
ABC/Wires