The decision means that U.S. President Barack Obama will leave office in early 2017 having extricated the country from the longest war in United States history.
Gunmen attacked the Indian Consulate in Herat province during which three attackers were killed.
The presidential run-off on June 14 falls at the height of the traditional summer fighting season.
Two top candidates will face each other after final results showed nobody polled more than 50% of the vote.
The assault comes two days before the results of a critical presidential election are set to be announced.
More than 2,000 people are believed buried in their homes.
Frontrunners Abdullah Abdullah and Ashraf Ghani are expected to face off in a 2nd round in late May.
The detention of the top Taliban negotiator looks to have stalled hopes to reignite the peace process.
The arrest of the top Taliban leader threatens Kabul's efforts to jump start the peace process.
Incident raises fears as to the capacity of security forces to maintain stability after international troops withdraw.
