Pakistan's military says the country's army chief met with U.S. Ambassador David Hale to express Islamabad's serious concerns over the drone strike that killed the former Taliban leader.

Wednesday's military statement says army chief Gen. Raheel Sharif denounced "such acts of sovereignty violations" as "detrimental to relations and counter-productive for the ongoing peace process."

Sharif insisted that "Pakistan's efforts, successes and sacrifices in fight against terrorism have been unparalleled."

Taliban leader Mullah Akhtar Mansour was killed inside Pakistan in the drone strike on Saturday that hit his vehicle in Baluchistan province. The airstrike strained relations between Pakistan and the United States.

On Tuesday, Pakistan's Interior Minister Chaudhry Nisar Ali Khan condemned the drone strike and claimed that Mansour was not an obstacle to peace talks.