Abdul Qadeer Khan, known as the father of Pakistan’s nuclear programme, died on Sunday after a brief illness at 85.
Pakistan President Arif Alvi said he was "deeply saddened" by the news of Khan's death. Pakistan's Defence Minister Pervez Khattak called it a "great loss".
The Pakistani atomic scientist was hailed as a national hero for making his country the world's first Islamic nuclear power, but was deemed dangerous by the West for smuggling technology to rogue states. He died after being transferred to hospital with lung problems.
A nuclear smuggling network led and operated by Khan had posed serious threat to Asian security. This network was allegedly responsible for providing atomic weapons designs and materials to states such as Iran and North Korea.
Khan was also at the centre of a massive global nuclear proliferation scandal. He was accused by then Pakistan army chief and president Pervez Musharraf of running a rogue proliferation network for nuclear material.
Shortly after Musharraf’s announcement, a recorded confession by Khan was aired in which he took sole responsibility for all the nuclear proliferation that had been revealed.