WikiLeaks was under cyber-attack Tuesday, several days after the rogue Web site released classified U.S. government documents to major newspapers around the world. According to a posting on its site, WikiLeaks was hit with a distributed denial of service (DDOS) strike of unknown origin. "DDOS attack now exceeding 10 Gigabits a second," said a WikiLeaks representative, in a message on Twitter.

Speculation about the source of the attack ranged from the U.S. government, to foreign regimes embarrassed by the information WikiLeaks disclosed to The New York Times, Der Spiegel, Le Monde, and other major newspapers.

None of the speculation, however, has been confirmed.

Among other things, the documents revealed serious concerns within the U.S. diplomatic community about the resolve and trustworthiness of several key allies, including Afghanistan and Pakistan, in the war on terror.

They also disclosed Saudi Arabia's wish for a U.S. military strike against Iran, and painted unflattering pictures of Western leaders like German Chancellor Angela Merkel and Italian Prime Minister Silvio Berlusconi.

In the wake of the leak, the White House ordered a security clampdown.

The administration is telling agency heads to develop stricter criteria for determining which federal employees are given access to secured computer systems and networks that store classified data.

"Our national defense requires that sensitive information be maintained in confidence to protect our citizens, our democratic institutions, and our homeland," said Office of Management and Budget director Jacob Lew, in a letter to agency heads. "Any failure by agencies to safeguard classified information pursuant to relevant laws, including but not limited to Executive Order 13526 … is unacceptable and will not be tolerated," wrote Lew. President Obama signed Executive Order 13526 on Dec. 29, 2009.

It mandates that federal agencies undertake a broad series of steps to protect information.