The State Department on Friday designated Pakistan's Haqqani network a foreign terrorist organization, opening the way for the use of new tools to thwart a complex enemy that has been responsible for some of the deadliest attacks against U.S. troops in Afghanistan while operating like an organized crime family.

The move by Secretary of State Hillary Clinton came after lengthy debate within the Obama administration, with some officials fearing the designation might make it more difficult to negotiate a peace settlement with the Haqqanis and their allies, the Taliban, as well as or put yet another chill on the United States' already fragile counterterrorism alliance with Islamabad. But negotiations have gone nowhere, and the CIA has been launching drone strikes at Haqqani targets, including an attack last month that killed Badruddin Haqqani, son of the group's leader.

"This designation could meaningfully impair the international fundraising and business efforts that allow the Haqqanis to fund their terrorist attacks, foreign fighter training and radicalization programs," said Jeffrey Dressler, an expert at a Washington think tank, the Institute for the Study of War.

A senior Obama official said the designation, which goes into effect within 10 days, does not prohibit U.S. officials from talking to the Haqqanis, a clan of Afghan Pashtun warlords based in Pakistan's tribal areas who operate across the border in Afghanistan. But Pakistani officials remain skeptical of Washington's commitment to peace talks, and designating the Haqqani network as a terrorist group will make negotiations less likely, a Pakistani official said.

Concerns about U.S. captive

The Haqqanis -- whom Adm. Mike Mullen, shortly before he retired as chairman of the Joint Chiefs of Staff, called a "virtual arm" of Pakistani intelligence -- agree. "It means the United States is not sincere in their talks," a commander was quoted as saying by Reuters.

Another commander said the move could also complicate talks to free Army Sgt. Bowe Bergdahl, the only U.S. prisoner of war from the Afghan conflict. Bergdahl, 26, of Idaho, has been held by the militants since his capture in 2009. State Department spokesman Patrick Ventrell dodged questions about reported Haqqani threats to further mistreat Bergdhal as a result of the designation but said the United States was doing everything it could to free him.

"He's just been held for too long," Ventrell said.

The decision nonetheless drew praise from Congress, which had required that the decision be made by Sunday.

Sen. Dianne Feinstein, D-Calif., who chairs the Senate Intelligence Committee, said the Haqqanis are responsible for deaths or injuries to more than 1,300 U.S. troops and have orchestrated a series of the terrorist attacks inside Afghanistan, including last September's assault on the U.S. Embassy and NATO headquarters. The group is also blamed in the 2008 kidnapping of New York Times reporter David Rohde.

"This is a critical step that clears the path for the United States to begin to put a choke hold on the network's finances," said Mike Rogers, R-Mich., who chairs the House Intelligence Committee.

Like a mafia network

That may not be easy. Rogers, who investigated the Chicago mafia as an FBI agent, has joined others in describing the Haqqanis as operating like a crime family, with illicit businesses in smuggling and drugs that would be difficult to sanction. But, like the mafia, the network also has legitimate businesses, including real estate, construction companies and car dealerships. The terrorist designation allows the U.S. to pressure companies or countries to stop doing business with the Haqqanis.

The Associated Press and New York Times contributed to this report.