NATO says aircraft entered Pakistan, killed "armed individuals"

KABUL (Reuters) - NATO aircraft crossed the border into Pakistan on Thursday morning and killed "several armed individuals," the alliance said in a statement, after Pakistan said a cross-border airstrike killed three border guards.

Aircraft from the NATO-led International Security Assistance Force (ISAF) initially crossed the border briefly while targeting suspected insurgents who were firing on a coalition base from a position inside Afghanistan, the statement said.

They were then fired on by people in Pakistan, and crossed the border again to target that group.

"Operating in self-defense, the ISAF aircraft entered into Pakistani airspace killing several armed individuals," the statement said.

The statement did not say if ISAF thought those killed were border guards, and when asked for clarification, an ISAF spokeswoman said both sides were still investigating the incident.

(Reporting by Sayed Salahuddin; Editing by Emma Graham-Harrison)