ISLAMABAD: Former Inter-Services Intelligence (ISI) chief Ahmed Shuja Pasha said that the drone attacks had their uses but it violated the national sovereignty.

They come in findings of the Abbottabad Commission investigation into how the al-Qaeda leader Osama bin Laden evaded detection for nearly a decade, which were published by the Al-Jazeera news network on Monday.

The former ISI chief said that there were no written agreements regarding drone strikes, however, he added that there was a political understanding between Pakistan and US.

The Americans had been asked to stop drone strikes because they caused civilian casualties, but "it was easier to say no to them in the beginning, but 'now it was more difficult' to do so," it quoted Ahmed Shuja Pasha as saying.

"Admittedly the drone attacks had their utility, but they represented a breach of national sovereignty. They were legal according to American law but illegal according to international law," the report quoted the former ISI chief as saying.