According to reports, Provincial Governor Zalmai Weesa was also killed in the attack; however, Afghan Interior Ministry has said that he was wounded and is being treated in a hospital.
Provincial police spokesman Salam Afghan confirmed the explosion had killed one person and wounded at least two.
Meanwhile, a North Atlantic Treaty Organisation convoy was attacked late Wednesday near the Afghan capital, killing two civilians and injuring five Czech troops, Afghan officials and the Czech military said Thursday.
The Taliban took responsibility for the attack, which also killed three of Mr Qahraman's companions in Lashkar Gah, the capital of Helmand province.
The Taliban has claimed responsibility for the attack at the security meeting. But the local commander of the NDS intelligence service and the Kandahar provincial governor Zalmay Wesa were also killed.
"After the meeting ended and as the officials were saying goodbyes, a member of the governor's team of bodyguards opened fire", Pashtun said. Gen. Harold J. Greene was killed and about a dozen US soldiers were wounded when an Afghan soldier opened fire inside a building in Kabul. His father and uncle were killed by the Taliban in 1994; he became the provincial police chief in 2011, after his predecessor was murdered in a suicide bombing.
"We need to find who's done this", Mr. Mattis told reporters traveling with him in the southeast Asian city-state of Singapore.
The Taliban has been perpetrating several attacks in the run up to the parliamentary elections.
"General Miller is uninjured", he added.
Prime Minister Imran Khan says, "Pakistan suffered similar attacks during its own electoral process and we can feel the pain of the people of Afghanistan".
Afghanistan witnessed a string of attacks ahead of the October 20 parliamentary elections. Two Americans were injured in the incident at the compound, a North Atlantic Treaty Organisation spokesperson said, and a local cameraman was reportedly killed. "Two Americans were wounded in the cross-fire and they have been medically evacuated", Col Knut Peters, a spokesperson for Nato's Afghanistan mission told The National. In an AP interview, his adviser, Ziaulhaq Amarkhil said the attack was meant to disrupt elections and urged voters to defy Taliban threats, saying casting their ballot "would be a big slap on the face of the enemy".
The election for parliament's lower house is seen as a dry run for the presidential vote scheduled for April and organisers have said it would not be delayed any further.