The death toll climbed to 20 in a complex attack on former interior minister and vice-presidential candidate Amrullah Saleh’s political office in Kabul, the Ministry of Interior confirmed.

The attack, which continued for six hours, left 50 others wounded, the Interior Ministry’s spokesman Nusrat Rahimi said, adding 16 of those killed were civilians.

At least four attackers were involved in the siege which started with a car bombing at around 4:40 pm Kabul time on Sunday. It targeted the Green Trend office, a political movement run by Mr. Saleh, in Shaheed Circle in Kabul’s PD4, in an area surrounded with civilian houses, a university, and a small township.

Mr. Saleh was in his office along with almost 100 people when the attack happened. He was sharply evacuated from the area.

Photos on social media showed Mr. Saleh with a stain of blood on his right arm.

The attack ended at around 11 pm on Sunday night after all four attackers were gunned down, according to the Interior Ministry’s spokesman.

The complex attack happened hours after Mr. Saleh attended the inaugural ceremony of their electoral campaigning with incumbent President Ashraf Ghani and the Second Vice President Mohammad Sarwar Danish. 

Chief Executive Abdullah Abdullah, a close political rival to Ghani’s team, paid a visit to Mr. Saleh’s house for an inquiry about his health, Abdullah’s spokesman Fraidoon Khwazoon said in a tweet on Sunday night.   

The incident was condemned by the Afghan government, the United Nations, former President Hamid Karzai as well as by governments of India and Pakistan.