A British soldier killed in an explosion in Afghanistan may have been the victim of so-called friendly fire, the Ministry of Defence has said.
The soldier, from 36 Engineer Regiment, died in the Sangin area of Helmand on Monday. His next of kin have been told.
The MoD said a smoke shell, designed to provide cover for soldiers working on the ground, "may have fallen short of its intended target".
An investigation has been launched to determine exactly what happened.
The soldier's death, announced earlier, took the total number of British military personnel killed on operations in Afghanistan since 2001 to 325.
An MoD spokesman confirmed the death was being investigated as a "suspected friendly fire incident".
"Initial reports suggest that a smokescreen was requested to enable the movement of elements of 36 Engineer Regiment who were operating on the ground in the Sangin area," he said.
"As this was being undertaken, it is believed that one of the smoke shells may have fallen short of its intended target.
"The investigation is now ongoing to determine the facts and no further comment will be made at this time."
Lt Col James Carr-Smith, spokesman for Task Force Helmand, said the serviceman had been part of a counter-IED (improvised explosive device) search team providing security in Sangin District.
"He died seeking to improve the lives of local Afghans. He will be sorely missed by his many friends. His sacrifice will not be forgotten. We will remember him," said Lt Col Carr-Smith.