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.
Officials said General Razeq and General Miller and the other officials were walking towards a landing zone as the helicopter taking the US General's party back to Kabul approached to land when the gunman, who was waiting outside, opened fire on the group. Earlier reports said the governor was killed.
He said the governor, Zalmay Wesa, was wounded and taken to the hospital.
"There was a situation at the Kandahar palace today".
Col Peters said initial reports indicated the original attacker is dead.
The Taliban claimed responsibility, and a Taliban spokesman said U.S. Gen. Scott Miller, commander of U.S. and North Atlantic Treaty Organisation troops in Afghanistan, was the target.
Mr. Mattis said he had yet spoken to Gen. Miller and could not confirm the Taliban's claim of responsibility. "We stand in solidarity with the fearless people of Afghanistan in fighting terrorism imposed on them".
Miller, 57, took over last month as the top USA commander in Afghanistan, replacing Gen. John W. Nicholson Jr.
"We need to find who's done this", Mr. Mattis told reporters traveling with him in the southeast Asian city-state of Singapore.More news: Cool Things the Pixel 3 Can Do
In a statement, the Taliban referred to Gen Raziq as a "brutal police chief".
The controversial Kandahar police chief, described by Human Rights Watch previous year as the southern province's "torturer in chief", had risen through the ranks to become one of the most powerful security heads in Afghanistan.
Now, the attack in Kandahar has diverted the attention of the country's security leadership to the province at a time when it is needed nationwide for the election.
They said that a member of the governor's compound guard had opened fire on Raziq and that a shootout involving Afghan and American security personnel had ensued.
He was accused of abuses, including torturing Taliban inmates, but had brought reasonable security in Kandahar, the birthplace of the Taliban militants.
However, the USA military said the attack would have no effect on its military presence aimed at bringing the Taliban to the negotiating table: "This attack will not change U.S. resolve in our South Asia strategy", Defense Department spokesman Lieutenant Colonel Kone Faulkner said.
The Taliban claimed responsibility for the attack in Bagram, which is the home of a sprawling USA military base.
Already, at least 10 candidates have been killed ahead of the election and while the Afghan government has promised to deploy 54,000 soldiers to protect the polls the Taliban has vowed to disrupt the election.