The unusually heavy barrage of three missile strikes in a span of 12 hours, targeting militant hideouts in north and south Waziristan took one of the largest death toll in the controversial unacknowledged air campaign.
The drone attacks commenced on Monday night when unmanned air craft unleashed nine missiles into a suspected militant compound and a vehicle in north Waziristan, killing 25 militants, local officials were quoted by TV channels as saying.
Few hours later, the drone struck again in nearby South Waziristan firing missiles and killing five militants.
The drones reappeared early this morning over the area firing two missiles at another compound in North Waziristan killing 15 militants.
It was the second largest death toll in drone campaign. In 2009 a missile attack killed 70 militants in south Waziristan.
The stepped up drone campaign follows on the heels of Obama Administration's announcement that it was suspending more than one-third of the massive USD 2 billion military assistance to Pakistan.
The three attacks in quick succession indicates that White House has no intention of stopping the drone campaign that has contributed to tensions between Washington and Islamabad.
Washington has called Pakistan's semi-autonomous North West Tribal Region as the most dangerous place on earth and the global headquarters of dreaded Al Qaeda and is pressing Islamabad to launch a full scale military operation in North Waziristan region to strike at Haqqani network faction of the Taliban.
But the Pakistan military claims that its troops are too over stretched by operations against Taliban in other areas to undertake such an offensive, but analysts believe that Islamabad is hesitant to cross militants with whom it has historical links and who could be useful allies in Afghanistan after foreign forces withdraw.
In response, the Obama Administration has dramatically increased drone strikes in North Waziristan over the past couple of years, besides also hitting South Waziristan.
A total of 21 US drone strikes have been reported in Pakistan's tribal areas since the US Navy SEALs killed world's most wanted fugitive and Al Qaeda chief Osama bin Laden in Abbottabad on May 2.