NEW YORK - The United States and Pakistan are engaged in a billing dispute of sizable proportions, with Washington rejecting over 40 per cent of the claims submitted by Islamabad as expenses to fight al Qaeda and other terrorists along the Afghanistan border, The Wall Street Journal reported Tuesday. Washington, increasingly dubious of what it sees as Islamabads mixed record against militants, has been quietly rejecting more than 40% of the claims submitted by Pakistan as compensation for military gear, food, water, troop housing and other expenses,: the newspaper said, citing internal Pentagon documents. Those records, it said, detail $3.2 billion in expense claims submitted to the US for operations from January 2009 through June 2010. According to the documents and interviews with officials, Pakistan has routinely submitted requests that were unsubstantiated, or were deemed by the US to be exaggerated or of little or no use in the war on terror-underscoring what officials and experts see as a deep undercurrent of mistrust between both nations, it added. For example, as per the paper, the Pakistani army billed the $50 million for hygiene & chemical expenses, of which the US agreed to pay only $8 million, according to records covering January 2009 through June 2010. Pakistans Joint Staff the countrys top military brass requested $580,000 in 2009 to cover food, medical services, vehicle repair and other expenses, but the US paid nothing. In one case in the past year, the US paid millions to refurbish four helicopters to help Pakistans army transport troops into battle against Taliban and other militants. But the Pakistanis ended up diverting three of those aircraft to peacekeeping duties in Sudanoperations for which Islamabad receives compensation from the United Nations, US officials said. This is about how much money Pakistan can extract, Moeed Yusuf, South Asia adviser for the United States Institute of Peace, an independent research organization funded by Congress, was quoted as saying. The billing spat has exacerbated tensions between the countries, which reached a nadir after the U.S. raided the compound of Osama bin Laden without informing Pakistani authorities, the Journal said. On Monday, Senate Foreign Relations Committee Chairman John Kerry in Islamabad said the U.S. wants to hit the reset button to warm relations between the countries. Pakistani officials deny they are trying to bilk the U.S. and say the increased American scrutiny has sent the message to the Pakistanis that Washington considers the army to be full of cheats. A senior Pakistani official called this detrimental to bilateral trust. The official says Islamabad understands the need for some scrutiny but said the U.S. has gone too far: People have to give a receipt for every cup of tea they drink or every kilometer they drive. Meanwhile, US officials say that Pakistani claims have been rejected for a number of reasons, including failure to confirm that expenses were incurred in support of American operations in Afghanistan and the war against terrorism. Some US officials also fear that some of the aid is being diverted to the border with India, the report said. Secret diplomatic cables obtained by WikiLeaks show that US officials were taken aback by Pakistani claims as early as 2006, including a 26-million-dollar charge for barbed wire and pickets, and for almost 70 million dollars in radar maintenance, although there is no enemy air threat related to the war on terror, it was pointed out. The documents show that denial rates have climbed from a low of 1.6 per cent in 2005, to 38 per cent in 2008 and 44 per cent in 2009. Claims are generally processed six months to a year after submission, said the report.