Pakistan's army spokesman said a cut in US military aid will not affect its ability to combat terror groups.
General Athar Abbas told the BBC that Islamabad had not yet been officially told of the reason for the $800m cuts or what they would entail.
The money equates to about a third of the annual US security aid to Pakistan.
Announcing the move on Sunday, the US said Pakistan was an important ally but that there were "difficulties" to overcome in their relationship.
White House Chief of Staff Bill Daley told ABC television that Pakistan had "taken some steps that have given us reason to pause on some of the aid".
Pakistan has long been considered a vital ally by Washington in the fight against al-Qaeda and Taliban militants, who use safe havens in Pakistan's tribal regions on the Afghan border.
But many in the US Congress have questioned the value of the more than $2bn in military aid sent to Islamabad each year, particularly following the discovery that al-Qaeda leader Osama Bin Laden managed to live undetected in the city of Abbottabad, almost next door to a major military academy.
The US operation to kill Bin Laden in May this year was carried out without Pakistan being informed in advance.
In a sign of their deteriorating relationship, Pakistan has since expelled more than 100 US military trainers and has threatened to shut down a CIA base.
General Abbas said he could not say which parts of the military would be worst hit until US officials told him what sections of aid were being cut.
But he said Pakistan's Army Chief had already been asking for military aid to be redirected towards civilian areas, where it is needed more.
The increasing US drone attack on militants inside Pakistan along the Afghan border is also a continuing source of antagonism - there are regular complaints of civilian casualties.
A New York Times article said some of the suspended aid had been earmarked as compensation for Pakistan's redeployment of troops to Afghan border areas to fight militants. Other cuts were in military equipment.
In figures submitted to the International Monetary Fund last autumn, Pakistan's defense expenditure in its 2010-2011 budget was put at $6.41bn - an increase of $1.27bn on the previous year.