Glass from shattered windows lay on the street near the explosion as police sealed off the area.
Senior health official, Saleem Rasouli says 23 people were killed and more than 20 were injured in the incident.
Representative of Herat province, Ghulam Farooq Naziri said the lawmaker from the same province, Rahima Jami was injured.
Another official put the death toll at 21 but noted that more than 45 injured in the incident.
The first suicide attacker blew himself up close to the 5th Directorate in the capital Kabul city and the second blast occurred few minutes later when security forces rushed to scene.
The Taliban, who have carried out frequent attacks in Kabul, claimed the blasts.
Taliban spokesman, Zabihullah Mujahid said that the fifth directorate’s vehicle was the target of the first attack, while police were targeted in the second.
The twin bombings come as Taliban fighters intensify their nationwide offensive against the US-backed government in Kabul.
Edited by Zack Arya