The U.S. Justice Department announced Thursday the forfeiture of some $28 million worth of bitcoins - the e-currency - that law enforcement authorities had seized from the Silk Road Web site specializing in the sale of illegal drugs.

The decision on Wednesday by federal Judge Paul Oetken allowed the government to keep 29,655 bitcoins seized in September during the crackdown on - and dismantling of - the Web site, according to a communique issued Thursday by the U.S. attorney for the southern New York district, Preet Bharara.

The value of bitcoins fluctuates greatly and the $28 million figure was established based on the online currency's present value.

The bitcoins were seized from computer equipment accessed during the operation to dismantle the network.

The communique added that the confiscation is a civil action, although the operator of the Web site, entrepreneur Ross Ulbricht, who was arrested last October, is facing criminal charges for allegedly directing an online drug trafficking and money laundering network.

In addition, U.S. authorities confiscated 144,300 more bitcoins - currently worth some $130 million - in the operation, but Ulbricht has challenged that seizure and is resorting to the courts to demand their return.

According to U.S. authorities, Silk Road used bitcoins - an electronic currency that is not backed by any state or government - to try and keep its black market activities secret. EFE