By Charles Haviland
BBC News, Kabul
The Nato-led force in Afghanistan, Isaf, says it has shot dead three Afghan civilians in two separate incidents in the east of the country.
Isaf said it deeply regretted the incidents in which, according to a spokesman, people had failed to heed warning signs not to approach.
Two civilians were killed and three others were injured at a checkpoint in Kunar province.
Another civilian was killed as he approached a convoy in Paktia province.
The Isaf statement said that in the first incident two Afghan civilians died after their truck, moving at high speed, approached an Isaf checkpoint in Kunar.
It said the truck was given several signals to stop but failed to do so and was, in Isaf's words, "engaged by the Isaf checkpoint", resulting in the death of the two people.
Isaf said the post had been set up because of intelligence reports of a pending truck attack on a local military base which followed earlier fighting nearby.
Isaf said the second incident happened further south in Paktia province when a man approached one of its convoys behaving suspiciously.
It said he ignored signs and shouts to stop and, on trying to evade capture, was shot dead by Isaf personnel.
In a separate incident in Nuristan province in the north-east, at least two police were killed in an insurgent ambush and a police commander was kidnapped, according to the deputy police chief.