A site on the notorious 'dark internet' is offering crowdfunded assassinations - with one public figure attracting a $126,000 (£75,000) bounty.

The website collects bitcoins - a digital currency - to fund the murder of political figures, and named targets include world leaders such as US President Barack Obama.

Details of the site were revealed in an in-depth report on the dark internet, the murky and anonymous parallel online network where illegal activity is rife.

It was compiled by the Washington-based Digital Citizens Alliance, which said the public figure who had amassed the largest bounty to date was not an elected official.

It declined to name the target, to avoid bringing "additional attention" to the person.

The website is run by someone calling themselves Kuwabatake Sanjuro who says he or she is motivated by "a deep-rooted hate against oppressive regimes".

The person added: "Once you're on the list you're on it until you die."

The site is an extreme example of some of the offerings on the dark internet, which is accessed using special software that can preserve anonymity.

Silk Road - the best-known dark website - was seized by the FBI in October last year, and alleged founder Ross Ulbricht was arrested.

The site was relaunched just a month later, and allows people to buy and sell illegal items ranging from class A drugs and deadly weapons to secret bank accounts and hacking services.

It is described by researchers as the "largest, most sophisticated criminal enterprise the internet has ever seen".

The report says the Silk Road has seemingly bounced back since the bust, with a higher number of drugs listed for sale now than in October.

Around 13,600 listings for drugs are on the site, compared to the 13,000 that were listed shortly before Ulbricht's arrest, the report says.