A top Republican congressman is calling on the State Department to designate WikiLeaks a "foreign terrorist organization," as he and several other lawmakers demand the Obama administration find a way to prosecute founder Julian Assange in the wake of the group's latest document dump.

WikiLeaks' weekend release of more than 250,000 classified State Department documents has outraged Washington officials. The spilling of secrets this time deals with a trove of candid diplomatic cables and other missives spanning everything from Pakistan to Iran to North Korea and could jeopardize the United States' sensitive foreign policy dealings.

Combined with the organization's prior mega-leaks of Iraq and Afghanistan war documents, the latest release is putting American lives in danger and breaking down the trust between the United States and its allies, lawmakers said. They urged the Obama administration to treat Assange and his operation severely.

New York Rep. Peter King, ranking Republican on the House Homeland Security Committee, urged Attorney General Eric Holder to prosecute Assange and urged Secretary of State Hillary Clinton to designate his group a foreign terrorist organization, in letters sent out over the weekend.

"This is extremely damaging to U.S. troops, U.S. interests and U.S. intelligence," King told MyFox New York on Monday.

He said that labeling the group a foreign terrorist organization would allow the United States to seize its assets and stop other entities from cooperating with it.

"They are engaged in terrorist activity. What they're doing is clearly aiding and abetting terrorist groups," King said. "Either we're serious about this or we're not."

Though Army Pfc. Bradley Manning is already being held in connection with a prior leak, King urged Holder in a letter Sunday to prosecute Assange under the Espionage Act.

Holder said Monday that the Justice Department is conducting an "active, ongoing, criminal investigation" into the situation. He condemned the leak and said it put national security at risk.

"To the extent that we can find anybody who was involved in the breaking of American law and who has put at risk the assets and the people that I have described they will be held responsible, they will be held accountable," Holder said.

Lawmakers on both sides of the aisle joined the call for tough legal action to be taken, though it's unclear whether the United States could win the cooperation of foreign governments to pull that off.

Sen. Joe Lieberman, I-Conn., chairman of the Senate Homeland Security and Governmental Affairs Committee, called the release "an attack on the national security of the United States." In a written statement released Monday, he said those behind the leak will have "blood on their hands" and recommended legal action.

"I also urge the Obama administration -- both on its own and in cooperation with other responsible governments around the world -- to use all legal means necessary to shut down WikiLeaks before it can do more damage by releasing additional cables," he said.

Sen. Claire McCaskill, D-Mo., speaking on "Fox News Sunday," urged the administration to go after the leakers "with the force of law."

"If you can prosecute them, let's try," Sen. Lindsey Graham, R-S.C., said.

The State Department document leak has triggered an administration review of how classified documents are kept and accessed. The leaked information did not so much drop any single bombshell as it did lay out in agonizing detail the behind-the-scenes discussions and observations beneath U.S. foreign policy. The documents showed U.S. allies speaking bluntly about the threat posed by Iran's nuclear program as well as some trash talk about German Chancellor Angela Merkel. It detailed U.S. concerns about Pakistan's nuclear program and the horse-trading involved with shipping Guantanamo Bay detainees abroad.

Rep. Pete Hoekstra, ranking Republican on the House intelligence committee, said the leak puts U.S. foreign policy in danger.

"Sometimes politics gets to be pretty ugly. These releases show the art of getting to an agreement and moving a policy forward," he told ABC's "Good Morning America." "These folks that we now deal with now may don't have the trust when they're dealing with the United States, what's done in secret will actually stay in secret."