NATO-led troops shot dead two Afghan farmers who were watering
their land in east Afghanistan, a police chief said.
Afghan President Hamid Karzai has said civilian casualties are the biggest cause of tension between him and his Western backers, who have about 70,000 troops in Afghanistan fighting a Taliban-led insurgency.
The two Afghans were killed late on Tuesday just outside Khost city, east of the capital Kabul, provincial police chief Abdul Qayum Baqizoi said, adding they were innocent civilian farmers tending their land.
A spokesman for NATO-led forces said the alliance was investigating an incident in Khost, but would not give any further details or information.
The incident follows a dispute between US military and the Afghan government over the deaths of five Afghans killed in the northern Kunduz province during a US raid last week.
Officials said the dead were not militants but employees of a district mayor, but US military said detailed intelligence had led them to a compound where they responded to hostile fire.
More than 2,100 civilians were killed in Afghanistan last year, 40% more than in 2007, the United Nations said. Around a quarter were killed by international forces it said.
Separately in Khost, a roadside bomb killed eight civilians aboard a minibus and wounded eight others, NATO-led forces said.