The helicopter crash that killed 17 Spanish peacekeepers in Afghanistan on Tuesday was most likely an accident, Spain's defence minister has said.
The cause of the crash is still uncertain
Jose Bono said that strong winds were the probable explanation of the accident near Herat.
Five other Spanish troops were hurt when a second Puma helicopter made an emergency landing near Herat.
The troops were on a training exercise ahead of parliamentary elections in September.
Mr Bono, who travelled to Afghanistan after the incident, said that "no hypothesis can be ruled out" but that strong winds were the "most likely" cause.
"Specialists in charge of the investigation do not see evidence pointing to an external attack. Rather, the existence of strong gusts of wind in the area at the time of the tragedy may have caused it, emerging as the most probable hypothesis," he said in a statement.
Mr Bono had earlier refused to rule out the possibility that the plane had come under attack.
But a senior Afghan military official said the helicopters were not shot down.
"What is clear for us is that there was definitely no attack by militants," Maj Gen Shar Mohammed Karimi told Associated Press.
"We suspect one of the helicopters may have accidentally hit the other while flying. The other possibility is that the choppers had technical problems," he said.
Spain has about 850 troops deployed in the country
A top Taleban commander, Mullah Dadullah, told Reuters their fighters had shot down the helicopter but his claims could not be verified.
Other reports after the accident mentioned a sandstorm, mechanical failure or a collision between the two helicopters as possible causes.
Afghan President Hamid Karzai said he was deeply saddened by the crash and said Afghanistan would "remember the services of these brave soldiers who have made sacrifices so that the people of Afghanistan could live in peace".
US State Department spokesman Sean McCormack said: "The United States salutes their sacrifice and values their partnership."
Spanish Prime Minister Jose Luis Rodriguez Zapatero also gave his condolences to the families of those killed.
Spain has about 850 troops deployed in the country.
The area around Herat is generally considered more stable than areas of southern and eastern Afghanistan where the Taleban are more active.
There are currently more than 8,000 troops serving with Isaf, which is largely concentrated around Kabul.