WASHINGTON — The Obama administration has decided to blacklist as a terrorist organization the Haqqani network, the militant organization responsible for some of the deadliest attacks against American troops in Afghanistan, several American officials said late Thursday.

The decision, which is expected to be announced as early as Friday, culminates nearly two years of spirited debate inside the administration that reached a peak in the past month under the pressure of a Congressional reporting deadline this Sunday.

Several State Department and military officials argued that designating the organization would help strangle the group’s fund-raising activities in countries like Saudi Arabia and United Arab Emirates and pressure Pakistan to open a long-expected military offensive against the militants.

Many other senior officials, including several in the White House, expressed deep reservations that blacklisting the group could further damage badly frayed relations with Pakistan, undercut peace talks with the Taliban and possibly jeopardize the fate of Sgt. Bowe Bergdahl, the only American soldier known to be held by the militants.