According to Afghan officials, the victims were working in the fields when the airstrike hit early Saturday morning.
The raid was carried out despite the security pact signed by Kabul and Washington on Tuesday.
Under the pact, Afghan forces must lead any night operations and night raids must be coordinated by Afghan forces.
Hundreds of civilians have lost their lives in the US-led operations in various parts of Afghanistan over the past few months, with Afghans becoming increasingly outraged at the seemingly endless number of the deadly assaults.
Afghan people have held mass rallies across the country to condemn such killings and to demand the complete withdrawal of foreign troops from Afghanistan.
However, the Tuesday pact signed by US President Barack Obama and his Afghan counterpart Hamid Karzai paves the way for American presence in the country until 2024.
The US-led invasion of Afghanistan was launched in 2001. The offensives removed the Taliban from power, but insecurity continues to rise across the country, despite the presence of thousands of foreign troops in the country.