Attorney general signs off raft of steps to help stem flow of leaked embassy cables as pressure mounts on site founder

International pressure on Julian Assange intensified tonight, as the US attorney general disclosed that he had authorised "significant" actions aimed at prosecuting the WikiLeaks founder over the release of thousands of diplomatic cables.

Eric Holder, who did not specify what these actions might be, also said his justice department was examining ways to stem the flow of leaked cables.

His comments came as a Swiss bank announced it had closed Assange's account because he had given "false information". Earlier the US-based commerce business PayPal also froze the WikiLeaks account. Assange has $61,000 (£38,000) in PayPal and $37,000 in the Swiss account, sources said.

The US attorney general, speaking at a press conference in Washington, said: "The lives of people who work for the American people have been put at risk. The American people themselves have been put at risk by these actions that I believe are arrogant, misguided and ultimately not helpful in any way. We are doing everything that we can."

Asked if he might mount a prosecution under the Espionage Act, Holder said: "That is certainly something that might play a role, but there are other statutes, other tools at our disposal." Holder added that he had given the go-ahead for a number of unspecified actions as part of a criminal investigation into WikiLeaks. "I personally authorised a number of things last week and that's an indication of the seriousness with which we take this matter and the highest level of involvement at the department of justice," he said.

He refused to say whether the Obama administration would try to shut down WikiLeaks. "I don't want to get into what our capabilities are," Holder said. "We are looking at all the things we can do to try to stem the flow of this information."

The Obama administration is facing criticism, mainly from conservatives, over what they claim is an inadequate response to WikiLeaks.

The Swiss bank that closed Assange's account today, Swiss PostFinance, the banking arm of the Swiss post office, said: "The decision comes after it was revealed that Assange provided false information regarding his place of residence when opening the account."

WikiLeaks had advertised the PostFinance account details online to "donate directly to the Julian Assange and other WikiLeaks Staff Defence Fund," giving an account name of "Assange Julian Paul, Geneve". The bank said there was no proof of residence.

The leaks have created major disruption and embarrassment at the US state department, throwing into question whether some of the more critical and candid diplomats can remain in post.

The Daily Beast website quoted an unnamed Obama administration source saying the state department is planning to recall some of them and that, in some cases, it would be dangerous for them to remain in their posts. "We're going to have to pull out some of our best people … because they dared to report back the truth about the nations in which they serve," a senior US national security official said, according to the Daily Beast.

A state department official did not confirm such moves were planned, only that staff would be transferred if necessary.

John Kerry, the Democratic chairman of the Senate foreign affairs committee, in a weekend interview, suggested he thought a reshuffle is necessary and that he would be advocating that behind the scenes.

The former US ambassador to Afghanistan, Zalmay Khalilzad, was more specific, saying comments made about corruption by the present incumbent, Karl Eikenberry, made him redundant as an interlocutor. A German political party has called for the US ambassador there to be brought home because of remarks he made about it.

John H Coatsworth, dean of Columbia university's school of international and public affairs (Sipa), today sent a note to students affirming that freedom of information and expression was at the core of the school's beliefs.

The school's office had sent out a warning from a state department official that their future job prospects could be jeopardised if they look at the leaked cables, which remain officially classified.

Coatsworth said: "Sipa's position is that students have a right to discuss and debate any information in the public arena that they deem relevant to their studies or to their roles as global citizens, and to do so without fear of adverse consequences. The WikiLeaks documents are accessible to Sipa students (and everyone else) from a wide variety of respected sources, as are multiple means of discussion and debate both in and outside of the classroom."

In a Time magazine poll, Assange is the leading contender to be named Person of the Year.