A pair of "escalation of force" incidents involving coalition forces in Afghanistan have left at least two Afghan civilians dead, officials said Wednesday.

As in Iraq, foreign troops in Afghanistan have come under repeated criticism by Afghans and the Afghan government for civilian deaths at checkpoints and around convoys.

In one of the incidents reported Wednesday, an Afghan driver was shot and killed in Khost "when he failed to comply with warnings to stop approaching forces," according to a news release issued by U.S. Forces Afghanistan.

"Combined forces were conducting operations when they observed a vehicle turning abruptly toward a security element. Afghan forces used verbal commands and gestures in an attempt to stop the vehicle. When the driver continued approaching, Afghan forces fired warning shots, but the man was undeterred."

Troops then fired on the vehicle, killing the driver, who was the only occupant.

In the second incident, one Afghan was killed and another wounded "when their vehicle appeared to threaten a coalition convoy," the U.S. command said.

"The coalition convoy warned the Afghans to slow down and move their vehicle away from the convoy by discharging a flare. The vehicle slowed and moved away, but then approached the convoy in a manner that again appeared threatening," the release read.

Two more flares were fired, then a warning shot, officials said. Two shots were then fired directly at the car.

"The coalition regrets the incident and loss of Afghan life, and has ordered an investigation," officials said.