The attack on December 6 killed 55 people and injured more than 160 outside a Shi'ite shrine in Kabul where hundreds had gathered to celebrate a religious holiday.
At least four people were killed in a near-simultaneous bombing in the northern city of Mazar-e Sharif.
The Kabul attack marked the first major assault on Afghanistan's Shi'ite minority in recent years.
Lashkar-e Jhangvi, a Pakistan-based group, has claimed responsibility.
The group is responsible for dozens of attacks against minority Shi'a in Pakistan, but the validity of the claim could not be immediately determined.
Visiting the wounded in the hospital on December 7, Karzai said he would raise the issue with the Pakistani leadership.
The attacks came one day after a major international conference in Germany on the future of Afghanistan.
compiled from agency reports