Islamabad: Pakistan has stopped seeking reimbursements from the US for its expenses on the war on terror since the May 2 American raid in Abbottabad that killed al-Qaeda chief Osama bin Laden, according to a media report on Tuesday.
The decision is likely to put additional burden on the resource-strained budget.
Pakistan used to claim between USD 100 million and USD 140 million a month as reimbursements from the US.
The unclaimed amount over the past six months is at least USD 600 million, provided activities in the war on terror are continuing at the same pace, The a newspaper quoted its sources as saying.
Pakistan was reimbursed for its expenses in the anti-terror campaign through the US Coalition Support Fund.
Even before the raid against bin Laden, the US has started delaying or rejecting some claims for reimbursement to put more pressure on the Pakistani government to act against militants.
The US rejected 35 percent to 40 percent of the claimed amounts before the raid in Abbottabad, unnamed officials said.
In the initial years of the war on terror, the US would disburse the entire amount.
Till December last year, the US had disbursed USD 8.6 billion to Pakistan, as against claims of USD 12 billion under the CSF, a government functionary said.
The last tranche of the CSF was released in December 2010, clearing claims for the period up to June 2010. The Pakistan government will now have to decide whether to show the rejected amount as outstanding or write it off.

Authorities have compromised on claims worth about USD 900 million and the total outstanding figure is USD 2.5 billion.
The government had initially estimated it would receive USD 1.4 billion from the CSF this year but the figure has been revised to USD 800 million, officials said.
"It is not aid. Rather, these are the expenditures that we have already incurred and it is our own money," a source told the daily.
Pakistan has raised the issue of mark-up costs on the withheld amount with US authorities, the officials said.
Pakistan has added USD 800 million in balance of payments calculations and any shortfall will increase the deficit on external payments and receipts.
The US has processed half of this amount but is waiting for the final nod from the Deputy Secretary of Defence.
After he gives clearance, the Department of Defense will notify the cleared amount to Congress, which has 15 days to either clear or block the amount.
The Congress earlier blocked USD 800 million from the CSF after the killing of bin Laden.
Pakistani officials said that during the first five months of the current fiscal year, the military has spent Rs 187 billion, or 38 percent of the allocated defence budget of Rs 495.2 billion.