The covert CIA drone program in Pakistan has been a constant source of tension between Islamabad and Washington. Pakistani officials regularly denounce the strikes in public as a violation of the country's sovereignty. But the government is known to have supported at least some of the attacks in the past. It is generally understood that Pakistan's secret agreement with the U.S. on drone strikes in the past was confined to the tribal region and did not include the country's so-called "settled areas."