The Obama administration, both independently and in concert with other governments, should "use all legal means necessary to shut down WikiLeaks before it can do more damage by releasing additional cables," Lieberman, Ind-Con., said Sunday in a statement.
"WikiLeaks' activities represent a shared threat to collective international security," he said.
Lieberman is the chairman of the Senate Homeland Security and Governmental Affairs Committee and a senior member of the Senate Armed Services Committee.
WikiLeaks posted about 250,000 diplomatic cables that revealed U.S. diplomats' dual role as spies is expanding. The WikiLeaks revelations include orders for State Department personnel to collect such data as credit card and frequent-flier numbers, work schedules and personal information from foreign officials overseas and at the United Nations, The New York Times reported Sunday.
"By disseminating these materials, WikiLeaks is putting at risk the lives and the freedom of countless Americans and non-Americans around the world," Lieberman said. "It is an outrageous, reckless, and despicable action that will undermine the ability of our government and our partners to keep our people safe and to work together to defend our vital interests."
Lieberman said it was "outrageous" for WikiLeaks and its backers "to hide their conduct behind the ideal of 'transparency.'"
"As a democracy, our nation has always believed the American people should have access to as much information as possible," he said. "But we have also long recognized that -- to keep our country safe -- some information must be kept secret."
WikiLeaks "short-circuited" the democratic process by publishing the cables and declaring itself the arbiter of what should and shouldn't be made public, Lieberman said.
"This is therefore not only an attack on our national security," he said, "but an offense against our democracy and the principle of transparency."