WASHINGTON — The Swiss bank PostFinance moved Monday to close WikiLeaks founder Julian Assange’s bank account in the latest international move to isolate him in the wake of his release of once-secret U.S. State Department cables.

Bank spokesman Alex Josty said the bank took the step after it determined that Assange, an Australian, wasn’t a resident of Switzerland as he’d declared when he opened the account. Josty said the bank re-examined the original paperwork after WikiLeaks, seeking donations, posted the account information on its website. “”It’s no problem for an Australian to have an account, but they have to live in Switzerland,”” Josty said.

Josty said the bank took the action on its own and that there had been no pressure from Swiss authorities for the bank to act. “”When we found out he had put the information on the website, it immediately became the focus of international attention, so that was the reason we took a look,”” Josty said in a phone interview. “”We acted with complete freedom.””

Under Swiss banking law, the involuntary closing of an account requires the approval of the Swiss Council of State and parliament, the bank said in a statement. That approval “”has yet to be granted,”” the bank said.

In the week since WikiLeaks began posting the State Department cables, in cooperation with newspapers in five countries, Assange has faced a series of actions intended to prevent the website from continuing to operate.

Amazon.com, after a phone call from U.S. Sen. Joseph Lieberman, I-Conn., canceled the hosting of the WikiLeaks website on its servers. The Internet payment company PayPal canceled WikiLeaks’ account and stopped accepting donations for the site. Interpol, the international police organization, issued a “”red alert”” seeking Assange’s arrest on sex-related charges in Sweden.

The WikiLeaks website, which was moved to a server in Switzerland, came under what’s known as a denial of service attack in which thousands of requests for information to a site render it unavailable to other users.

In a statement posted to its Twitter account, WikiLeaks said that Assange had $43,000 in his Swiss bank account when it was frozen and said that PayPal had frozen another $84,000 that had been intended for WikiLeaks.

WikiLeaks, however, remained available in much of the world. More than 500 so-called “”mirror sites”” had been established in the past 24 hours to carry the site, WikiLeaks said.

In addition, the site posted what it called an insurance policy — all 251,287 documents in an encrypted file that anyone could download. The file, however, is unreadable without a 256-digit password. WikiLeaks said it would make the password public if Assange were killed. It was unknown how many times the full file had been downloaded.

The furor over WikiLeaks seems unlikely to end anytime soon. By WikiLeaks’ count, as of Monday it had released only 913 of the State Department documents it’s holding.