WASHINGTON — The Obama administration declared Friday that the Pakistan-based Haqqani network of militants is a terrorist body despite misgivings about how the largely symbolic act could further stall planned Afghan peace talks or put yet another chill on the U.S.’s already fragile counterterrorism alliance with Islamabad.

Secretary of State Hillary Clinton’s decision, signed Friday ahead of a Sunday deadline set by Congress, bans Americans from doing business with members of the group and blocks any assets it holds in the U.S. The order, which will go into effect within 10 days, completes an odyssey of sorts for the Haqqanis from the days they partnered with the CIA during the Cold War and were hailed as freedom fighters.

Clinton, whose advisers were of two minds about whether the designation was the right path, said in a statement Friday the U.S. will “also continue our robust campaign of diplomatic, military and intelligence pressure on the network, demonstrating the United States’ resolve to degrade the organization’s ability to execute violent attacks.”

A subsidiary of the Taliban and based in the remote North Waziristan region of Pakistan, the Haqqani network is responsible for several attacks in Kabul, including last September’s rocket-propelled grenade assault on the U.S. Embassy and NATO headquarters.

U.S. officials estimate its force at 2,000 to 4,000 and say it maintains close relationships with al-Qaida.

U.S. defense officials said the administration doesn’t believe the Haqqanis have designs to attack the United States. But they said the group shelters al-Qaida and other militant groups, allowing them to plan and train for possible operations targeting the U.S.

The U.S. already has sanctioned many Haqqani leaders and is pursuing its members militarily. But it resisted the terrorist designation because of worries it could jeopardize reconciliation efforts between the U.S. government and insurgents in Afghanistan, and ruffle feathers with Pakistan, the Haqqanis’ longtime benefactor.

U.S. officials have held talks with Ibrahim Haqqani, the brother of the network’s founder, Jalauddin Haqqani, to try to further peace talks with the Taliban, said two U.S. officials familiar with the negotiation attempts. The designation does not stop the U.S. from meeting with the Haqqanis, who’ve been among the least interested in talking reconciliation before American troops make an almost complete withdrawal from Afghanistan by the end of 2014, officials said.