The first attacker hit a bus with Afghan National Army officers, killing seven and wounding 15 in west Kabul, said Kabul criminal investigation police chief Mohammad Farid Afzali.
The second attacker, who was also on foot, blew himself up in front of a second bus in northeast Kabul, wounding additional army personnel, Afzali said.
Taliban spokesman Zabihullah Mujahid claimed responsibility for the attacks. They came a day after Afghanistan and the U.S. signed a security pact allowing U.S. forces to remain in the country past the end of the year to support Afghans as they take over the fight against the Taliban insurgency.
Under the pact, along with a separate deal signed with NATO, about 10,000 American troops and several thousand more from other NATO countries will stay to train and advise Afghan forces after the international combat mission ends December 31.
More than a decade after U.S. forces helped topple the Taliban in the wake of the September 11 attacks, Afghanistan is still at war with the Islamic militant group, which regularly carries out attacks, mainly targeting security forces.