The United States is trying to expand a secret CIA operation designed to eliminate radical Islamic militants' havens located in Pakistan near the Afghan border, The Wall Street Journal reported.

Citing unnamed senior officials, the newspaper said that in recent weeks the administration of President Barack Obama had asked Pakistan to allow additional Central Intelligence Agency officers and special operations military trainers to enter the country to intensify pressure on militants.

The requests have so far been rebuffed by Islamabad, which remains extremely reluctant to allow a larger US ground presence in Pakistan, the report said.

On Friday, the United States made a new bid to improve its uneasy war partnership with Pakistan by offering a two-billion-dollar arms package but warned it will not tolerate human rights abuses.

The five-year assistance plan satisfies a key request of Pakistan's influential military, which assists the US military in Afghanistan and was initially uneasy about a US shift to civilian assistance.

Secretary of State Hillary Clinton said Friday that the US administration would ask Congress to approve two billion dollars in military aid from 2012 to 2016, replacing an earlier five-year package that expired.

The number of CIA personnel in Pakistan has grown substantially in recent years, The Journal said. But the exact number is highly classified.

According to the paper, there are currently about 900 US military personnel in Pakistan, 600 of which are providing flood relief and 150 of which are assigned to the training mission.

A senior Pakistani official said relations with the CIA remain strong but Islamabad continues to oppose a large increase in the number of American personnel on the ground, The Journal said.