"A police vehicle was also attacked in the Nad Ali district of Helmand killing five people.
"In Helmand, there have been intensified operations by international troops, both the British and American offensives have been going on in the last month."
The wedding party blast on Wednesday came as Anders Fogh Rasmussen, the new Nato leader, visited Afghanistan, his first trip to the country since taking over as head of the Western military alliance.
He later travelled to the southern city of Kandahar.
|Thousands of Nato troops are conducting offensives in Helmand [AFP]
Rasmussen said that he was determined to reduce civilian casualties, which have caused widespread anger among Afghans against US and foreign forces in the country.
He said "pragmatic steps" were needed to improve Afghan security, and that if it took "talks with a number of groups within the Afghan society, I am ready to do that".
Rasmussen said Nato would support Afghans when they assume control from the US-led military operation in Afghanistan for "as long as it takes".
But he said doing so means "helping them stand on their own feet".
Thousands of Nato troops are conducting offensives in Helmand an area where roadside bombs are frequently used to attack foreign and Afghan forces.
Attacks on security forces have increased as Afghans gear up for a presidential election scheduled for August 20.
However, the attacks have come mainly in the south where Taliban fighters have their strongest presence.