In terms of the original cut-off date of December 6, 1993 none of them qualified for amnesty.
Mandela told reporters in Pretoria he would ask parliament next year to approve the extension of the date to May 10, 1994. The deadline for amnesty applications to the Truth and Reconciliation Commission would be moved to May 10 next year.
Nine people were killed by a car bomb detonated near the headquarters of the African National Congress and the Pan Africanist Congress in central Johannesburg on April 24 1994.
The victims included an ANC election candidate.
Six polling stations around the country were bombed the same day, and more blasts went off the next day.
On April 26, a powerful car bomb exploded outside the international departures area at Johannesburg International Airport about 20 minutes after polls opened for special votes. Thirteen people were injured.
The extension also opens the way for amnesty applications from those responsible for the Shell House shootings in central Johannesburg on March 28.
Shots were fired in a clash between ANC security guards and Inkatha Freedom Party marchers in violence which left at least 53 people dead. Eighteen of them were killed in the city centre.