Whistleblower website WikiLeaks co-founder Julian Assange has said that the website is suspending its publication of classified files to fight the ‘unlawful’ financial blockades led by the US, and to raise funds via the conventional banking system.

Assange said at a news conference in London that the financial blockade is a "dangerous, oppressive and undemocratic" attack led by the US, which had deprived WikiLeaks of "tens of millions of dollars." He added that though it might seem that credit card companies are based in different countries such as the UK, the reality is that almost all credit card companies are controlled in the US.

Assange said the blockade posed an existential threat to WikiLeaks and the organisation would be "simply not able to continue" unless the blockade is not lifted or the enough funds are raised via conventional banking system. He warned, "If WikiLeaks does not find a way to remove this blockade, we will not be able to continue by the turn of the new year."

WikiLeaks publishes confidential documents – mostly related to governments — from whistleblowers. It is believed that finance companies in the US have blocked funding for the whistleblower site. This comes after WikiLeaks’ disclosure of hundreds of thousands of secret US government files and diplomatic cables on the Internet.

Assange alleged that since last December, financial companies, including Visa, MasterCard, PayPal and Western Union, have refused the transactions of donations to WikiLeaks through their systems. He said this move has blocked "95 percent" of the website’s revenue. Last year, hacker group Anonymous rose to prominence after it unleashed a series of DDoS-based attacks on the credit card companies in protest of the blockade. Last month, the hacker group had promised a "fitting reply" to governments for not acting on DDoS attacks on WikiLeaks.

Assange revealed that the website has been functioning on its cash reserves for the past 10 months. He said WikiLeaks must "aggressively fundraise in order to fight back against this blockade and its proponents".

"A handful of US finance companies cannot be allowed to decide how the whole world votes with its pocket," he added.

A WikiLeaks spokesman, Kristinn Hrafnsson said that it is hoped that the website would reopen on 28 November, said the BBC.

In March, Assange had said that the Internet is "the greatest spying machine the world has ever seen" while speaking to students at Cambridge University in the UK. He had said, "It is not a technology that favours freedom of speech. It is not a technology that favours human rights. Rather it is a technology that can be used to set up a totalitarian spying regime, the likes of which we have never seen."

Assange is in Britain awaiting a decision by the High Court on the appeal against his extradition to Sweden, where he faces sexual assault charges relating to alleged incidents in Stockholm in August 2010. Assange has maintained that the allegations as "without basis".

In August, a spate of cyberattacks crashed the whistleblower website. An AP report said that the cyberattack took place after the "accelerated publication" of tens of thousands of sensitive US State Department cables. The report added that WikiLeaks had published over 125,000 secret documents in the past week, which was far more than it had earlier published.

State Department spokeswoman Victoria Nuland had condemned the leaks. She told reporters, "The United States strongly condemns any illegal disclosure of classified information."

"In addition to damaging our diplomatic efforts, it puts individuals’ security at risk, threatens our national security and undermines our effort to work with countries to solve shared problems. We remain concerned about these illegal disclosures and about concerns and risks to individuals.

"We continue to carefully monitor what becomes public and to take steps to mitigate the damage to national security and to assist those who may be harmed by these illegal disclosures to the extent that we can." she said.

WikiLeaks had responded: "Dear governments, if you don’t want your filth exposed, then stop acting like pigs. Simple."