KABUL — A car bomber struck a coalition convoy outside a base in southern Afghanistan Thursday, hours after a visit by Defense Secretary Leon E. Panetta.
There were no indications the suicide bombing near Kandahar Air Field was connected to the visit by Panetta, who arrived in Kabul on Wednesday. His day trip to Kandahar on Thursday was not publicized in advance and garnered little media attention as it was taking place. Panetta never left the base.
At a late evening news conference with President Hamid Karzai, Panetta said the attack killed one US service member and wounded three others.
Javed Faisal, a spokesman for the governor of Kandahar Province, said the attack also killed three Afghan civilians and wounded 18.
Panetta said the bomber rammed a heavily armored vehicle called an MRAP.
There was no immediate claim of responsibility.
Also Thursday, Afghan officials said the powerful chief of the country’s spy service was airlifted to the United States to be treated for wounds sustained in an attempted assassination last week.
Militants have claimed responsibility for the attack on the official, Asadullah Khalid, at a Kabul guest house by a Taliban suicide bomber.
Khalid survived but his abdominal wounds were grievous.
Shafiqullah Tahiri, a spokesman for the National Directorate of Security said Khalid left Afghanistan on Wednesday.
Khalid was flown out aboard a military transport configured to carry severely wounded soldiers.
He was taken to a US military hospital at Landstuhl, Germany, and would be moved to United States in the coming days, the coalition said.
Karzai has suggested the insurgents were aided by Pakistan’s intelligence service in their attempt to kill Khalid, an ethnic Pashtun who was one of the militants’ most implacable and, in the view of many coalition officials, effective foes.
The Taliban draws almost all its support from Pashtuns, the ethnic group to which Karzai also belongs.
In Khalid’s absence, the National Directorate of Security is being run by one of his deputies, General Hisaamuddin Khan, an ethnic Tajik who fought Taliban rule in the 1990s.
Panetta also announced that President Obama had invited Karzai to visit Washington the week of Jan. 7 to discuss a ‘‘shared vision of Afghanistan beyond 2014,’’ when the NATO mission expires.
The goal is an enduring US military presence expected to focus on training and support to Afghan security forces, and likely to include a small US counterterrorism contingent.
The US proposal is expected to total no more than 10,000 troops, despite the desire of some military officers for a larger force.
As part of any deal, the United States is demanding that its service personnel be subject to US military law, not Afghan law, something that has rankled the Afghans.
The Afghan government is seeking a number of compromises from the United States to assure its sovereignty, including power over detention facilities and detainees.
Karzai and Panetta repeated expressions of confidence a deal can be reached.