The scientist described as the father of Pakistan's nuclear bomb was given a state funeral on Sunday at the country's largest mosque. Abdul Qadeer Khan died earlier in the day at the age of 85.
The ceremony for the man regarded as a national hero in Pakistan took place at Faisal Mosque in Islamabad. The national flag was flown at half-mast at the parliament building and elsewhere in the capital.
Many people took part, including an elementary school student who said Khan made nuclear weapons that have kept Pakistan safe from its enemies.
Khan helped the country conduct a successful nuclear test in 1998.
He came under severe international criticism in 2004, when it was discovered that he had played a role in sharing nuclear technology with foreign countries, including North Korea and Iran.