The authorities in Chile have arrested four people who the police say are members of one of the world's most successful groups of computer hackers.

The men are accused of breaching more than 8,000 websites, including that of US space agency Nasa. One of the men, who has used the alias "Net Toxic", is alleged to be one of the most prolific hackers in the world.

The men were detained in simultaneous raids in three cities in Chile, including the capital Santiago. The Chilean police carried out the operation in co-ordination with Interpol and intelligence services from the US, Israel and several Latin American nations. The arrests came after an investigation lasting eight months, Chilean officials said.

The four men also allegedly managed to infiltrate the websites of the Chilean finance ministry and Berkley University in the US.

And they are accused of gaining access to government websites from a range of other countries, including Venezuela, Turkey and Israel.