ISLAMABAD: Pakistan's foreign policy chief believes the militants have been weakened by an army offensive and now operate mostly out of Afghanistan.

Sartaj Aziz , national adviser for foreign affairs, spoke a day after U.S. National Security Adviser Susan Rice warned leaders in Islamabad that attacks in Afghanistan by militants based in Pakistani threaten regional security.

U.S. officials particularly expressed concern about the Haqqani network , which they blamed for several bloody bombings and attacks in the Afghan capital in recent weeks.

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Aziz denied any implication that Pakistan is not targeting the Haqqani network - an Islamist movement allied with both al Qaeda and the Taliban - in its military offensive in the border region of North Waziristan.

"The infrastructure of the Haqqani network in North Waziristan, which included the IED (improvised explosive device) factories and a number of other capacities including communication, has been disrupted," Aziz told a joint press briefing with the visiting German foreign minister.

He also disputed the assertion by U.S. officials that the Haqqanis plan most of their Afghanistan attacks from Pakistani soil.

"Our assessment is that their capacity in Afghanistan is much, much bigger - probably 80/90 percent compared to what it is here. And what is here is also being cleaned out as a part of our operations," Aziz said.

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Pakistan has long denied sheltering the Haqqani network , despite the top U.S. general in 2011 calling the militants a "veritable arm" of Pakistani military intelligence.

Pakistan's army has been waging an offensive against the Taliban and other militants in North Waziristan for more than a year, but some critics question whether the Haqqani leadership was allowed to leave ahead of the assault.

Monday's remarks came amid uncertainty on whether the U.S. would release $300 million in military aid to Pakistan, which is dependent on U.S. government certification that Pakistan is targeting the Haqqanis.