On Twitter, he wrote "we strongly condemn the terror attacks in Afghanistan yesterday. They are an attack on Afghanistan's multicultural fabric. My thoughts are with the bereaved families. I pray that the injured recover soon. India stands ready to assist the Afghanistan government in this sad hour."
A suicide bomber targeted the convoy on their way to meet Afghanistan's president in the eastern city of Jalalabad.
Police chief Ghulam Sanaei Stanikzai told Pajhwok Afghan News that the suicide bomber detonated his explosives when the minority community members wanted to enter the governor's house to meet President Ashraf Ghani, who was visiting the region.
"We strongly condemn the heinous and cowardly terrorist attack in #Jalalabad today evening which resulted in the death of 20 innocent Afghans, including 10 members of the Afghan Sikh Community, and injured more than 20 persons," the Indian Embassy in Kabul tweeted.
"We convey heartfelt condolences to the families of the victims and pray for early recovery of the injured...The attack again underlines the need for united global fight against international terrorism without discrimination and accountability of those who support terrorists in any manner," it said.
Avtar Singh Khalsa, a longtime leader of the Sikh community who had planned to run in the parliamentary elections set for October, was killed in the attack.
(with input from agencies)