At least one other senior Afghan official was killed in the audacious assassination strike that was claimed by the Taliban and underscored the harrowing insecurity in Afghanistan two days before the elections and more than 17 years after the militant group was driven from power. A Taliban spokesman said Miller was the intended target.
However, Army Col. David Butler, who attended the meeting with Miller, said the powerful Kandahar police chief, Abdul Raziq, was clearly the target, not the U.S. general.
"It was pretty clear he was shooting at Raziq," Butler told The Associated Press, adding that Miller was nearby but not in the line of fire.
The delegates had just gathered for a group photo when gunfire broke out inside the provincial governor's compound in Kandahar city, according to an AP television cameraman who was there. Everyone scattered, and the U.S. participants scrambled toward their helicopter. But a firefight broke out between the U.S. service members and Afghan police when they tried to stop the U.S. delegation from reaching their helicopter, said the cameraman.
Besides Raziq, Kandahar's intelligence chief, Abdul Mohmin was killed in the attack, according to deputy provincial governor Agha Lala Dastageri. He said Kandahar Gov. Zalmay Wesa also died after being taken to a hospital, although security officials in the capital maintained Wesa was wounded but survived.
Three Americans - a U.S. service member, a coalition contractor and an American civilian - were injured and in stable condition, said NATO spokesman U.S. Col. Knut Peters.
Taliban spokesman Qari Yousuf Ahmadi said the militant group carried out the attack, and Miller was the target.
Butler, however, said the assailant shot at Raziq and then appeared to spray the area with gunfire before he was killed.
He said Miller and the Afghan leaders had moved outside the palace after several hours of meetings and were standing in small groups in the compound. He said he heard several shots "and we all took cover. It was over in seconds."
"We stabilized and treated the wounded and secured the area," said Butler, adding that Miller made sure the scene was secure and the wounded were taken away by medivac before he left the area and returned to Kabul.
Razik was a particularly powerful figure in southern Kandahar and a close U.S. ally despite widespread allegations of corruption. He ruled the former Taliban heartland with an iron fist and had survived several past assassination attempts, including one last year that killed five diplomats from the United Arab Emirates.
Raziq's killing "may have major implications on the security situation in southern Afghanistan. As the chief of police in Kandahar, he has kept a lid on the Taliban's insurgency, which has intensified over the past several years," analyst Bill Roggio wrote in the Long War Journal.
The Taliban have vowed to disrupt Saturday's parliamentary elections, warning teachers and students not to allow schools to be used for polling and warning Afghans to stay away from the polls.
Within hours of the attack, Afghan President Ashraf Ghani addressed the nation to assure Kandahar residents it was safe to go to the polls. 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."
At a news conference in Kabul, army chief Gen. Mohammad Sharif Yaftali said additional troops had been moved from neighboring Helmand province to Kandahar.
U.S. Defense Secretary Jim Mattis said the killing of the Kandahar police chief is unlikely to fundamentally weaken the security situation. Speaking while in Singapore for a conference, Mattis called Raziq's death a tragic loss but said he believes the Afghan security forces have matured to the point where they can continue fighting the Taliban without him.
The U.N. Security Council condemned the attacks and others recently in Afghanistan and said violence or threats intended to disrupt the elections were unacceptable.
Pakistan's new prime minister, Imran Khan, and its military chief condemned the assault.
"The people and the security forces of Afghanistan have been paying a heavy price due to continued instability and threats from the enemies of peace," Khan said in a statement. "Pakistan stands by the government and the people of Afghanistan in their quest for lasting peace and stability."
Security has been steadily deteriorating in Afghanistan with increasingly brazen attacks being carried out by insurgents and Afghanistan's security forces have been on high alert ahead of Saturday's elections.
Late Wednesday, a NATO convoy was attacked near the Afghan capital, killing two civilians and injuring five Czech troops, Afghan officials and the Czech military said Thursday.
The attack in the Bagram district of Parwan province, also wounded three Afghan civilians, said Wahida Shakar, spokeswoman for the provincial governor.
The Taliban claimed responsibility for the attack in Bagram, which is the home of a sprawling U.S. military base.
In recent months, Afghan troops have come under near-daily attacks. NATO troops, which handed over security to Afghan forces at the end of 2014, mostly train and assist with air power. So far this year, eight U.S. soldiers and three other NATO service members have died in Afghanistan.
Associated Press writers Lolita Baldor in Washington and Karel Janicek in Prague, Czech Republic, contributed to this report.
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