Omar Zwak, spokesman for the governor of Helmand province, says five civilians, two soldiers and a policeman were killed in today's attack in the Sangin district.
Nine others, including four civilians, four soldiers and a policeman, were wounded in the blast.
Helmand has been the scene of heavy fighting in a number of poppy-producing districts including Sangin since the army launched a major operation against Taliban strongholds last month.
No one claimed responsibility for today's attack. Taliban fighters are expected to step up attacks as the traditional spring fighting season approaches.