The Obama administration on Friday laid out a five-year, $2 billion military aid package for Pakistan as it pressed the Islamabad government to step up the fight against extremists there and in neighboring Afghanistan.

Secretary of State Hillary Rodham Clinton announced the plan at the end of the latest round U.S.-Pakistani strategic talks. The administration will ask Congress for $2 billion for Pakistan to purchase U.S.-made arms, ammunition and accessories from 2012 to 2016, Clinton said.

The new military aid replaces a similar but less valuable package that began in 2005 and expired on Oct. 1. It will complement $7.5 billion in civilian assistance the administration has already committed to Pakistan over five years, some of which has been diverted to help the country deal with devastating floods.

The U.S. hopes the announcement, made by Clinton with Pakistani Foreign Minister Shah Mahmood Qureshi at her side, will reassure Pakistan of the long-term U.S. commitment to Pakistan's military needs. The aid also should help Pakistan bolster its efforts to go after Taliban and al-Qaida affiliates on its territory.

Although the exact terms of the deal are still being negotiated, the goal is to ramp up U.S. military aid to Pakistan incrementally over the five-year period.

The new aid package will not benefit Pakistani military units suspected of human rights abuses. The Obama administration already has cut off aid to some Pakistani units over concerns they may have been involved in abuses that include extrajudicial killings and torture, a senior U.S. official said late Thursday.

The official said aid to a handful of Pakistani units believed to have committed, encouraged or tolerated abuses was suspended under 1997 legislation championed by Sen. Patrick Leahy, D-Vt. The so-called Leahy Amendment bars U.S. military assistance from going to foreign armed forces suspected of committing atrocities.

"In accordance with the Leahy Amendment, we have withheld assistance from a small number of units linked to gross human rights violations," the official said. He also said the U.S. encouraged Pakistan to improve its human rights training.

The official spoke on condition of anonymity because he was not authorized to speak publicly on the matter.

It was not immediately clear when the decision to withhold the assistance was first made or exactly how many Pakistani military units were affected.

This week's talks in Washington — the third round of the U.S.-Pakistan Strategic Dialogue — came as the countries tried to ease tensions over American military incursions across the border from Afghanistan and allegations that Islamabad is not doing enough to target Taliban militants.

The U.S. has signaled that its patience is running out with Islamabad's reluctance to fight insurgents, a stance that has not changed despite billions of dollars in American aid.

During the last round in Islamabad in July, Clinton announced more than $500 million in aid for a variety of projects, including renovating hospitals, improving water distribution and upgrading hydroelectric dams. The U.S. had to re-examine its plans after the meeting, however, after Pakistan was hit by the worst floods in the country's history.