Speaking with the media after attending President Mamnoon Hussain's address to a joint session of Parliament, Sharif said: "US drone strikes in Pakistani territory are regrettable and must stop."
Sharif's comments on the drone strikes comes in the backdrop of US drone strike in Balochistan on May 21 that killed Mansour.
Hailing Mansour's death as an "important milestone" in efforts to bring peace to Afghanistan, US President Barack Obama has said that American forces would continue to go after threats on Pakistani soil.
Sharif also said the operation against the militants was going on successfully.
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"We have to maintain the victories of Operation Zarb-i-Azb. Terrorists will not be allowed to re-enter into areas cleared in South Waziristan and North Waziristan," he said.
General Sharif said that the border management with Afghanistan was improving and urged Afghanistan to take matching measures on its side of the border.
He said that the security situation in the country, especially in Karachi city and Balochistan province was improving.
Earlier, the army chief attended the joint session of the parliament to listen the address of the president.
The session was also attended by the chiefs of navy, and air force.