Afghan and U.S. soldiers patrol Afghan villages and ask about Taliban and Haqqani network activity in the area in the Paktika Province, Afghanistan in October 2011. (Joshua Partlow/THE WASHINGTON POST)

Congress wants the State Department to list the the Pakistan-based Haqqani network as a terrorist organization or explain why it refuses to do so.

The House gave unanimous approval late Tuesday to a bill forcing the Obama administration to take a position, an action that follows Senate passage of the measure in December. The bill now goes to President Obama, who has not announced his position on the matter.

The State Department has been studying since last year whether to add the Haqqani network to a list of foreign terrorist organizations, but has yet to render a decision. The legislation, first introduced last year by Sen. Richard Burr (R-N.C.), forces the Obama administration to either add the group to the list of terrorist organizations, or provide a detailed justification to Congress as to why it won’t be added.

The administration already has designated a number of the group’s leaders as terrorists and imposed sanctions on them, State Department spokesman Patrick Ventrell said last week.

“We haven’t taken a decision on the wider issue that’s still under review, but clearly, we’ve put the pinch on all the key leaders,” he said.

Based just across the eastern border of Afghanistan, the Haqqani network is considered the most dangerous insurgent force fighting U.S. troops in the region. It has maintained ties with militant organizations spanning the border, including al-Qaeda, part of an alliance that has helped make the Haqqani group particularly worrisome for U.S. officials.

The group is responsible for some of the larger and more dramatic attacks on U.S. installations in Afghanistan, including one on the U.S. Embassy last year, according to U.S. officials.

(RELATED: What is the Haqqani network?)

In an effort to quell the violence, U.S. officials met secretly last summer with members of the group to gauge whether they could be enticed to join peace talks aimed at ending the violence in Afghanistan. Despite those talks, U.S. diplomats in Afghanistan warned earlier this year in secret cables that the Haqqani network’s persistence was undermining the success of the American strategy in Afghanistan.

Complicating any decision, the group maintains close ties to Pakistan’s Inter-Services Intelligence (ISI), the nation’s top spy agency, and some observers say that adding Haqqani to the list of terrorist organizations would be considered one step short of declaring Pakistan a state sponsor of terrorism.

The United States is on course to reduce the size of its military force in Afghanistan to about 68,000 troops later this year and to eventually shift from a combat focus to an advisory role to the Afghan government and its military forces. The drawdowns will put heavy pressure on the Afghan government in the east, where U.S. and Afghan forces have struggled to curb violence, in part because insurgents can flee across the border to Pakistan, U.S. officials said.

Jason Ukman contributed to this report.

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