The Taliban denied responsibility for the blast |
At least 36 people protesting against the governor were also wounded in the attack early on Thursday, including Humayoun Humayoun, a well-known member of parliament from Khost.
Demonstrators in Khost have called for the ouster of the the acting governor of the province, Abduljabar Naeemi, whom they accuse of rampant corruption and land grabbing. Protests have been staged outside his residence for nearly a week.
The Taliban denied responsibility for the blast on the Twitter account of spokesman Zabihullah Mujahid, the AFP news agency reported.
The number of civilians killed and wounded in Afghanistan jumped 22 percent in 2014, a recent UN report said.
The United Nations Assistance Mission in Afghanistan attributed the rise to an intensification in ground fighting, resulting in a total of 10,548 civilian casualties last year.
US President Barack Obama last week reversed plans to withdraw around 5,000 US troops from Afghanistan this year.
Source: AFP