The Afghan capital has been relatively peaceful since the presidential election on June 14, though there have been street demonstrations as politicians are locked in a dispute over vote fraud.
"A suicide bomber targeted an ANA (Afghan National Army) bus this morning killing five ANA officers and wounding four in the west of Kabul," Sediq Sediqqi, spokesman for the interior ministry, told AFP.
"Five civilians were also wounded. It was an ANA airforce vehicle."
Election day saw a sharp rise in nationwide violence, but there has not been a major attack in Kabul since June 7, when 12 people were killed in a suicide strike against presidential candidate Abdullah Abdullah, who escaped unharmed.
Abdullah has said he will reject the result of the on-going vote count, alleging massive fraud against him in the election race against his rival Ashraf Ghani.
NATO's 50,000-strong combat force will leave Afghanistan by December, though about 10,000 US troops will stay into next year if the new president signs a security deal with Washington.