The US has increased the frequency of drone attacks in Pakistan's tribal regions bordering Afghanistan over the last few months.

More than 40 drone air raids have taken place since the beginning of last year, most of them since September.

More than 320 people have been killed in the raids, according to a tally of reports from Pakistani security officials, district government officials and residents.

Drone co-operation

Islamabad says the drone flights are an affront to Pakistan's territorial sovereignty and that they harm efforts by the government to deal with Taliban- and al-Qaeda-led fighters.


Pakistan fights to keep sovereignty over war

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But the US military on Thursday confirmed newspaper reports that it had shared with Islamabad surveillance data from drones flying over Pakistani territory.

Admiral Mike Mullen, chairman of the US joint chiefs of staff, said at a US senate hearing that Pakistan had requested surveillance support missions up until April.

"In terms of support and information, they have asked for that, and where they have asked for that, we've supported them," he told the Senate Armed Services Committee.

"Those requests have ceased over the period of about the last month."

The New York Times had earlier reported that the US military had shared intelligence data from drones with the Pakistani military.

Reports 'accurate'

Mullen said the newspaper report was an "accurate portrayal" of co-operation between Washington and Islamabad.

However, the Pakistani military has strongly denied that it is co-operating with US forces in the deployment of the drones.

"In terms of Pakistani control of or liaison with those drones, the Pakistani military is absolutely adamant - they are operating completely by themselves in this campaign [against the Taliban] and are receiving no help from any outside force," Mike Hanna, Al Jazeera's correspondent in Islamabad, said.

"There appears to be a very keen realisation, by the military in particular, that this [current] campaign is dependent on public support, and of ongoing political support within this [country's] divided political nexus."