The Taliban issued a claim of responsibility for the attack shortly afterwards.
Bus blast fatalities
The blast comes a day after eight Afghan civilians were killed by a roadside bomb that hit their minibus in the eastern province of Paktia.
The explosion occurred in a Taliban-held area late on Sunday, killing women and children who were travelling on the bus, witnesses said.
Police sources told Al Jazeera that eight people were killed in the blast and 14 others wounded. Survivors were taken to the provincial hospital for treatment.
Hours earlier Afghanistan's interior ministry had warned that civilian deaths were on the rise in the country. New figures showed that there were 173 civilian deaths between March 21 and April 21 this year, a 33 per cent increase on the same period in 2009.
The statistics did not record who was responsible for the deaths but the UN has said that the Taliban are responsible for most civilian deaths in Afghanistan.
Anger over deaths
Deaths caused by international troops the country have caused widespread anger in the country.
The US revised its rules on using air attacks and other weaponry last year after facing criticism for accidently killing civilians during operations against the Taliban.
Last week, the French military admitted responsibility for the deaths of four civilians who were killed during a clash with Taliban fighters on April 6.
The attack was followed by a controversial incident on April 20 in which Nato troops fired on a vehicle that approached their convoy, killing four civilians.
A recent US report confirmed the jump in civilian deaths in recent months.