A Taliban suicide bomber blew himself up next to a collection of shop stalls inside an eastern Afghan army base on Sunday, killing two NATO service members and at least two civilians, officials said.
The Taliban claimed responsibility, saying it was a suicide attack by a Taliban sleeper agent who had joined the Afghan army so that he would be able to kill foreigners.
The explosion occurred in an area of the Gardez army base where shopkeepers sell goods to both Afghan soldiers and their partnered NATO troops, said Rohullah Samon, a spokesman for the Paktia provincial government.
NATO said in a statement that two members of the military coalition died in the suicide attack. They did not identify the victims or give their nationalities. Most of the NATO forces in Gardez are American.
Two shopkeepers were killed and at least 18 people were wounded in the blast, Samon said. He said he did not have information on any military deaths.
A Taliban spokesman said in an e-mail sent to media outlets that the civilians who were killed were not innocent because they had collaborated with government and NATO forces.
"They were at the service of the foreigners," Zabiullah Mujahid said.
In southern Afghanistan, another NATO service member was killed in an insurgent attack while an Afghan employee of an American contractor was shot dead in the city of Lashkar Gah, officials said. NATO did not provide any further details on the dead service member.
The victim in the Lashkar Gah shooting worked for International Relief and Development, said Daoud Ahmadi, a spokesman for the Helmand provincial government. The company, known as IRD, works on infrastructure and other aid projects for the U.S. government.
The killing comes after an attempted attack on the IRD office in March during which two would-be suicide attackers tried to storm the building. Those attackers were killed by security guards before they could enter the building.