"President Ghani condemns the Kabul terrorist attack with the strongest words, termed a despicable and crime against humanity," Sediq Sediqqi wrote on Twitter.
Ghani called on the Taliban to stop killing innocent Afghans. A spokesman for the militants denied they were involved in the Saturday bombing, which killed 63 people and wounded more than 150 others.
The president declared Tuesday the national day of mourning, Tolo News broadcaster reported earlier in the day.
