No group has so far claimed responsibility for the attack. PHOTO: AFP/FILE
The victims - among them four children and a woman - were killed when a bomb detonated against their Toyota sedan in Baraki Barak district of Logar province.
"As a result of the blast today afternoon, seven members of a family - all civilians - were martyred," Logar provincial police chief Abdul Hakim Ishaqzai told AFP.
Mohammad Rahim, the district governor of Baraki Barak, confirmed the fatalities.
Read: Suicide blast kills at least 13 in east Afghanistan: officials
No group has so far claimed responsibility for the attack, but roadside bombs have been a weapon of choice for the Taliban in their battle against the US-backed government and foreign forces.
The incident comes after a roadside bomb killed another Afghan family of seven - including three children - in the nearby restive province of Ghazni on Monday.
Roadside bombs often target Afghan security forces, but they have also taken a heavy toll on civilians.
The number of civilians killed and wounded in Afghanistan jumped 22 per cent in 2014, a recent UN report said, as NATO troops withdrew from combat.
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.
President Barack Obama last week reversed plans to withdraw around 5,000 US troops from Afghanistan this year, an overture to the country's new reform-minded leader, President Ashraf Ghani.
The Taliban, waging a deadly insurgency since they were ousted from power in late 2001, warned that the announcement would damage any prospects of peace talks as they vowed to continue fighting.
Afghan forces are bracing for what is expected to be a bloody summer push by the Taliban.
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