San Francisco, Jul 20 (AP) A medical evacuation drill at a California military base turned into a real emergency when two US Army Blackhawk helicopters participating in the exercise blew down four large tents and injured 22 Army Reserve soldiers, officials said today.

No one was seriously injured in the mishap Wednesday night at Fort Hunter Liggett, though two soldiers had to be airlifted to a hospital for treatment as others troops provided medical care.

"They were equipped and trained to immediately jump in, and they were quickly able to respond to the situation," said Master Sgt. Valerie Resciniti, an Army spokeswoman.

Injuries included cuts and bruises, sore shoulders, injured limbs and non-serious head trauma, Col. David Heflin said.

That wasn't what was supposed to happen as the 228th Combat Support Hospital out of San Antonio, Texas, participated in the medical evacuation training exercises happening throughout the service this month.

The military was investigating why the choppers were so close to the nylon tents that collapsed from the wash of the rotors.

Photos of the scene showed the green tents, which can sleep up to 40 people, partially crumpled and tent stakes ripped from the ground.

The tents were not fully occupied when they came down, Resciniti said.

Twenty soldiers were evacuated to the Fort Hunter Liggett Troop Medical Center and neighboring hospitals, Heflin said. All were released from the hospital by Thursday.

The accident occurred during annual training exercises for about 8,000 Army Reserve soldiers and military troops from Canada, the United Kingdom, Saudi Arabia and Colombia.

The 20-day combat support training exercise ends July 27.

Fort Hunter Liggett is about 170 miles (270 kilometers) south of San Francisco. The sprawling base is the largest U.S. Army Reserve Command post. (AP) CPS

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