A Pakistani air force spokesman said Indian aircraft violated Pakistani airspace but were chased back over the border.
The incident Saturday comes amid heightened tensions between the nuclear-armed rivals over last month's deadly attack in Mumbai.
India has said the Mumbai attack, which left more than 170 people dead, had roots in Pakistan.
Pakistan Air Commodore Himayun Viqar said the Indian aircraft crossed the border in Pakistan-controlled Kashmir and over the eastern city of Lahore.
He would not say how many Indian aircraft were involved or give the exact time.
Pakistan Information Minister Sherry Rehman said the Indian Air Force had told Pakistan the incursion was "inadvertent."
Comment from India was not immediately available.