San Francisco - A new anonymous Internet marketplace for illegal drugs debuted on Wednesday, with the same name and appearance as the Silk Road website shut down by US law enforcement authorities a month ago.

Like its predecessor, the new Silk Road listed hundreds of advertisements for marijuana, cocaine, ecstasy and other illegal drugs available for purchase from independent sellers using the anonymous Bitcoin digital currency.

On October 1, the Federal Bureau of Investigation shut down the original Silk Road and arrested its alleged mastermind, Ross William Ulbricht, 29, known online as "Dread Pirate Roberts," in San Francisco.

"It took the FBI two-and-a-half years to do what they did ... but four weeks of temporary silence is all they got," a site administrator wrote, also using the "Dread Pirate Roberts" moniker.

The FBI declined to comment on the new version of the Silk Road. For more than two years, the original site acted like an eBay of vice, allowing users to buy and sell illegal goods and services on the assumption that they were safe from the law. Deliveries were made through the mail in discrete packages.

US authorities also say Ulbricht had tried to call out a hit on a user who had threatened to expose the identities of thousands of Silk Road users.

Ulbricht's lawyer on Wednesday said his client would plead not guilty to drug trafficking, hacking and money laundering charges.

The charges against Ulbricht said his website generated sales of more than 9.5 million Bitcoins, roughly equivalent to $1.2 billion.

The new website improves on technology from the previous Silk Road meant to keep identities secret, including measures to keep users from losing their Bitcoins in case the site shuts down, according to the new Dread Pirate Roberts.

Senator Tom Carper, a top lawmaker on the Homeland Security committee, who plans to hold a hearing on digital currencies this month, said the new Silk Road site shows that government needs to adapt to fast-moving technology.

"Rather than play 'whack-a-mole' with the latest website, currency, or other method criminals are using in an effort to evade the law, we need to develop thoughtful, nimble and sensible federal policies that protect the public without stifling innovation and economic growth," Carper said in a statement.

A week after authorities shut down the Silk Road, British police said they arrested four men accused of being significant users of the site.

Two weeks ago, federal prosecutors said 144,336 Bitcoins were discovered on Ulbricht's confiscated computer, adding to more than 30,000 Bitcoins previously seized.

With the digital currency trading at an all-time on Wednesday, those Bitcoins were worth close to $50 million, according to the Mt Gox trading website.

Like the original Silk Road, users access the new site using a no-cost, anti-surveillance service known as the Tor network instead of traditional web browsers.

The relaunched Silk Road will soon hire staff to handle marketing for the site, the administrator mentioned in his post.

"The Silk Road has risen once more. ... Open communication with your old suppliers and customers, let this wonderful news be taken to all corners of the Tor Network and beyond," the person wrote.