The attack came on the first day of campaigning for Afghan presidential elections. (AFP)

India on Sunday strongly condemned the terror attack on the office of Afghan president Ashraf Ghani's running mate Amrullah Saleh in Kabul.

The attack came on the first day of campaigning for Afghan presidential elections.

"India strongly condemns the terrorist attack in Kabul today in which a number of innocent Afghans were killed. India expresses its deepest condolences with the families of the deceased," the Ministry of External Affairs said.

"This dastardly attack was also aimed at undermining the constitutional and democratic processes and institutions in Afghanistan," the foreign ministry said.

It said India stands in solidarity with the government and the people of Afghanistan in their efforts to achieve enduring peace, security and stability in the country.