"Pakistan has accepted US money, weaponry and limited training, but has rebuffed further US efforts to assist its forces," The Washington Post said in a report.

Although the US military flies Predators – separate from those directed by the CIA – along Afghanistan-Pakistan border, it is prohibited from overflying Pakistani territory, the paper said.

At the same time, the US has turned down Pakistani requests for its own Predators, it said.

According to the report US forces offered a compromise to Pakistan that it could direct US military Predators over areas of its choice, transmitting images directly into its own intelligence channels.

After Pakistan refused to allow a downlink to be established on its side of the border, ground equipment was set up at a joint cooperation centre on the Afghanistan side.

Pakistani officials were taken to Turkey to observe a similar programme, it said.

"It was somewhere between March 10 or 15 that we flew the first 'proof of concept' mission for the Pakistanis and said, 'Here's how the system would work. Here's how we can push data through your own networks so you would have capability available to you," a senior US military official was quoted as saying.

After a dozen odd missions were flown over the tribal regions near the border in mid-April, the Pakistanis abandoned the project.

"They just did not ask for additional flight information. Any time we have asked them if they need anything, they've come back and said, 'No, thank you.'" the official was quoted as saying.

A Pakistani official, according to the Post, said his government expected the programme to continue eventually but that its attention was now focused on the ongoing Swat offensive.

US over flights there were not wanted, he said. "We don't want the American UAVs (unmanned aerial vehicles) going so deep" into Pakistani territory, the Pakistani official said.