Secretary-general of the North Atlantic Treaty Organization (NATO) said on Sunday that the alliance's airstrikes that killed and wounded dozens of Pakistani soldiers on Saturday were "unintended."

"This was a tragic unintended incident. I fully support the ISAF (International Security Assistance Force) investigation which is currently underway. We will determine what happened, and draw the right lessons," Anders Fogh Rasmussen said in a statement.

The NATO chief said following "the regrettable incident," he had written to Pakistan's Prime Minister Yousaf Raza Gilani to say that the deaths of Pakistani personnel were "as unacceptable and deplorable as the deaths of Afghan and international personnel."

A total of 24 Pakistani soldiers were killed and 13 others injured when NATO fighter jets and helicopters bombed two border posts in Mohmand tribal region near the Afghan border early Saturday morning.

Rasmussen stressed the joint interest of NATO and Pakistan "in the fight against cross-border terrorism and in ensuring that Afghanistan does not once again become a safe haven for terrorists."

"NATO remains strongly committed to work with Pakistan to improve cooperation to avoid such tragedies in the future...NATO and Pakistan share a common goal: a stable Afghanistan in a peaceful region," he said.

VietNamNet/Xinhuanet