Afghan officials say a sticky bomb attached into a bus has detonated in the capital, Kabul, killing five people and wounding 10.

Nasrat Rahimi, spokesman for the interior ministry, says Monday's attack targeted a bus carrying government employees,

Wahidullah Mayar, spokesman for the public health ministry, stressed that these were only initial casualty reports that could still rise.

No one immediately claimed responsibility for the attack, but both Taliban and Islamic State militants are active in Kabul and have staged attacks there.

A wave of attacks has rocked the Afghan capital over the last week. Four bombings on Sunday killed at least two people and wounded 27, preceded by deadly suicide bombings on Thursday and Friday.