Story highlights A witness says a ceremonial hut caught fire; "you only heard men screaming"

Military helicopters airlift injured victims for medical treatment

11 members of an indigenous tribe were killed by a lightning strike, authorities say

"Nothing like this has ever happened here," the sister of one victim says

A lightning strike killed 11 members of an indigenous tribe in northern Colombia Monday after an electrical storm broke out during an early morning ritual.

Helicopters airlifted 13 injured people to hospitals for treatment, Gen. German Saavedra told reporters.

The lightning struck around 3 a.m. Monday during a ritual of the Wiwa community's government in the remote Sierra Nevada mountains, CNN affiliate Caracol TV reported

Bernardo Gil Moscote, a member of the community, told Colombia's El Tiempo newspaper that villagers were gathered in a ceremonial hut to discuss problems the community was facing. He had stepped out to get a drink when he heard crashing thunder that shook the mountains.

"When I got back, the hut was on fire," he told the newspaper, "and you only heard men screaming."

Colombian President Juan Manuel Santos tweeted his condolences and said military and police helicopters were evacuating the victims.

"I know that this is normal, that it is something that comes from nature, but nothing like this has ever happened there," said Marta Cecilia Gil, who tearfully told Caracol her brother and brother-in-law died in the lightning strike.