WASHINGTON -- The government scrambled Tuesday to prevent future spills of U.S. secrets like the embarrassing WikiLeaks' disclosures, while officials pondered possible criminal prosecutions and Interpol in Europe sent out a "red notice" for nations to be on the lookout for the website's founder.

Meanwhile, Interpol placed Julian Assange on its most-wanted list after Sweden issued an arrest warrant against him as part of a drawn-out rape probe -- involving allegations Assange has denied. The Interpol alert is likely to make international travel more difficult for Assange, whose whereabouts are publicly unknown.

In Washington, the State Department severed its computer files from the government's classified network, officials said, as U.S. and world leaders tried to clean up from the leak that sent America's sensitive documents onto computer screens around the globe.

By temporarily pulling the plug, the U.S. significantly reduced the number of government employees who can read important diplomatic messages. It was an extraordinary hunkering down, prompted by the disclosure of hundreds of thousands of those messages this week by WikiLeaks, the self-styled whistleblower organization.

The documents revealed that the U.S. is still confounded about North Korea's nuclear military ambitions, that Iran is believed to have received advanced missiles capable of targeting Western Europe and -- perhaps most damaging to the U.S. -- that the State Department asked its diplomats to collect DNA samples and other personal information about foreign leaders.

While Assange, the founder of WikiLeaks, taunted the U.S. from afar on Tuesday, lawyers from across the government were investigating whether it could prosecute him for espionage, a senior defense official said. The official, not authorized to comment publicly, spoke only on condition of anonymity.

There have been suggestions that Assange or others involved in the leaks could be prosecuted under the Espionage Act, but the question could be complicated. Who and what is he and his website? He has portrayed himself as a crusading journalist, and the Justice Department has steered clear of prosecuting journalists for publishing leaked secrets.

Meanwhile, State Department spokesman P.J. Crowley sought to reassure the world that U.S. diplomats were not spies, even as he sidestepped questions about why they were asked to provide DNA samples, iris scans, credit card numbers, fingerprints and other deeply personal information about leaders at the United Nations and in foreign capitals.

Diplomats in the Paraguayan capital of Asuncion, for instance, were asked in a secret March 2008 cable to provide "biometric data, to include fingerprints, facial images, iris scans, and DNA" for numerous prominent politicians. They were also asked to send "identities information" on terrorist suspects, including "fingerprints, arrest photos, DNA and iris scans."

In Burundi, Rwanda and the Democratic Republic of Congo the requests included information about political, military and intelligence leaders.

"Data should include e-mail addresses, telephone and fax numbers, fingerprints, facial images, DNA, and iris scans," the cable said.

Every year, the intelligence community asks the State Department for help collecting routine information such as biographical data and other "open source" data. DNA, fingerprint and other information was included in the request because, in some countries, foreigners must provide that information to the U.S. before entering an embassy or military base, a U.S. official said, speaking on condition of anonymity to discuss intelligence matters.

The possibility that American diplomats pressed for more than "open source" information has drawn criticism at the U.N. and in other diplomatic circles over whether U.S. information-gathering blurred the line between diplomacy and espionage.

"What worries me is the mixing of diplomatic tasks with downright espionage. You cross a border ... if diplomats are encouraged to gather personal information about some people," U.N. Secretary-General Ban Ki-moon said.

Crowley said a few diplomatic cables don't change the role of U.S. diplomats.

"Our diplomats are diplomats. Our diplomats are not intelligence assets," he repeatedly told reporters. "They can collect information. If they collect information that is useful, we share it across the government."

World leaders, meanwhile, were fielding questions about candid U.S. assessments of their countries.

In Kenya, the government was outraged by a leaked cable, published by the German magazine Der Spiegel, in which Kenya is described as a "swamp of flourishing corruption." Kenya's government spokesman called the cable "totally malicious" and said the State Department called to apologize.

In Brazil, officials declined to answer questions about U.S. cables that characterized the South American country as privately cooperative in the war against terrorism, even as it publicly denies terrorist threats domestically.

WikiLeaks has not said how it obtained the documents, but the government's prime suspect is an Army Pfc., Bradley Manning, who is being held in a maximum-security military brig on charges of leaking other classified documents to WikiLeaks. Authorities believe Manning defeated Pentagon security systems simply by bringing a homemade music CD to work, erasing the music, and downloading troves of government secrets onto it.

While world leaders nearly universally condemned the leak, the U.S. and Assange traded barbs from afar. In an online interview with Time magazine from an undisclosed location, Assange called on Secretary of State Hillary Rodham Clinton to resign because of the cables asking diplomats to gather intelligence. "She should resign, if it can be shown that she was responsible for ordering U.S. diplomatic figures to engage in espionage in the United Nations, in violation of the international covenants to which the U.S. has signed up," he said.

In France, Lyon-based Interpol placed the 39-year-old Assange on its most-wanted list, sent around the world.

His lawyer, Mark Stephens, a prominent media attorney in Britain, said an appeal by Assange remains pending in Sweden, and the lawyer is waiting for prosecutors there to "contact us and with details of the allegations and evidence."

Crowley, at the State Department, showed disdain for Assange.

"I believe he has been described as an anarchist," he said. "His actions seem to substantiate that."

Defense Secretary Robert Gates played down the fallout from the leaks, calling them embarrassing and awkward but saying they would not significantly complicate U.S. foreign policy.

"The fact is governments deal with the United States because it's in their interest, not because they like us, not because they trust us and not because they think we can keep secrets," Gates said Monday.

Crowley would not say how long the State Department would keep its files off the classified network.

"We have made some adjustments, and that has narrowed, for the time being, those who have access to State Department cables across the government," he said.