Islamabad: US drones targeted three militant compounds in the lawless North Waziristan tribal region on Friday killing at least 18 insurgents, just a day after Pakistan summoned a top American diplomat to lodge protest over such attacks calling them a violation of its sovereignty.
The CIA-operated spy planes targeted the militant compounds in Shawal region of North Waziristan tribal agency, which has witnessed a series of drone attacks in the past few weeks.
Eighteen people were killed in the strikes, state-run Radio Pakistan reported.
The drones fired two missiles at each of the compounds. The spy planes continued hovering over the area after the attacks.
Officials told the media that the death toll could rise.
Friday's attacks came a day after Pakistan's Foreign Office summoned a senior US diplomat to protest a string of drone strikes since last week, saying the attacks by the spy planes were unlawful and a violation of the country's sovereignty.
The US embassy was "demarched on recent drone strikes in North Waziristan. A senior US diplomat was called to the Ministry of Foreign Affairs and informed that the drone strikes were unlawful, against international law and a violation of Pakistan's sovereignty," said a brief statement issued by the Foreign Office spokesman.
"It was emphatically stated that such attacks were unacceptable," the statement said.
Over 20 militants have died in four earlier drone strikes in North Waziristan since August 18.
Ten militants were killed in two drone strikes in North Waziristan on August 19.
Most of the attacks were carried out in Shawal area.
The region is dominated by Hafiz Gul Bahadur's fighters, who often target US and other foreign troops in Afghanistan.
The US has been pushing Pakistan to act against Taliban and al-Qaeda elements in North Waziristan.
US Defence Secretary Leon Panetta recently claimed that Pakistan was preparing an operation against the Taliban in North Waziristan.
However, Pakistan Army Chief Gen Ashfaq Parvez Kayani has said his forces will undertake an operation in North Waziristan "at a timeframe of our choosing and determined only by our political and military requirements."
No operation will be launched due to "outside pressure," he said.