Attackers blew up and then stormed the political office of Amrullah Saleh, a former Afghan spy chief turned politician who is now the running mate of Afghan President Ashraf Ghani.
At least one person was killed and 13 wounded when the blast hit the office in central Kabul on the first day of campaigning for presidential elections in September.
Mr Saleh was lightly wounded by shrapnel and then evacuated from the office by his bodyguards. Photographs shared on social media showed him surrounded by bodyguards and with a small injury to his right arm.
Mr Ghani said: "My brother, true son of the Afghan soil and first vice president candidate of my electoral team, Amrullah Saleh, has survived a complex attack by enemies of the state. We are relieved and thank the almighty that attack has failed."
Mr Saleh has been a vociferous opponent of the Taliban and Pakistan, and led Afghanistan's NDS intelligence agency before joining politics with the Green Trend movement.
"At around 4:40 pm (1210 GMT), first a blast occurred near Green Trend office... then a number of attackers entered that office," interior ministry spokesman Nasrat Rahimi told AFP.Saleh belongs to Afghanistan´s Green Trend party and has previously served as the head of the country´s intelligence agency.
