Pakistan on Wednesday released 562 Afghans who had been jailed in the southern city of Karachi for up to six months on charges of illegal immigration.
The release came ahead of Afghan President Hamid Karzai's arrival on Wednesday in Islamabad for a three-day visit.
The Jail official Anwar Rizvi said the Afghans were taken by 12 buses to the border. They were escorted by police and Afghan diplomats.
The Afghans had been arrested in and around Karachi, Pakistan's biggest city and commercial hub, in the past six months as part of a crackdown on illegal workers.
Afghan diplomat Abdul Muqtadir Frozenfur said only 17 Afghan children, aged 10-14, remained in custody in Karachi on visa offences.
They were kept in a detention facility separate from the adult prison.
Negotiations were continuing for their release, he said.