Delmer Berg, the last known American survivor who fought fascists in 1930s Spain, has died in northern California. He was 100 years old.

Berg died on Sunday at his home in Columbia, Marina Garde from the Abraham Lincoln Brigade Archives in New York confirmed in a written statement.

The Modesto Bee reported on Tuesday that friend Pat Cervelli said Berg, who she knew for three decades, became politically active early in life.

Berg was among about 2,800 members of the Abraham Lincoln Brigade who sought to defend an elected government from a military rebellion led by General Francisco Franco. The rebellion was successful, and Franco led Spain for decades.

Berg stayed in Spain several months. He told the Modesto Bee in a November interview why he made the decision to help the Spanish working people.

“I was a worker,” Berg told the newspaper. “I was a farmer. I was in support of the Spanish working people, and I wanted to go to Spain to help them.”

He was wounded in a bombing at a monastery.

Born in Anaheim on 20 December 1915, Berg spent part of his childhood on a farm near Manteca. Later, he lived in Modesto and was the only white member of the local chapter of the National Association for the Advancement of Colored People.

Berg worked on housing discrimination and other issues and was a communist most of his life, drawing inquiries from the FBI, the newspaper reported.

Berg served two stints in the US military: once in the national guard before going to Spain and again in the East Indies during the second world war.

He later worked as a landscaper and a stonemason. He and his wife, June, who preceded him in death, even built a home of stone and reused lumber.

During his retirement, Berg was an activist against nuclear weapons and US involvement in Central America, and monitored an election in Namibia.

He became the last known survivor after John Hovan of Rhode Island died in 2014, according to the Abraham Lincoln Brigade Archives.