Police say Amin Abdullah, 51, a security guard at the largest mosque in San Diego County, sacrificed his life to keep ​140 children inside the mosque school safe by engaging two gunmen in a shootout and transmitting ​the radio call that activated a security lockdown.

Mosque elder Mansour Kaziha, 78, and ⁠Uber driver Nadir Awad, 57, a neighbour whose wife is a teacher at the mosque school, were also shot ​and killed in what is being investigated as a hate crime.

Funerals for the three are to be held on ​Thursday.

“When I learned about it … I couldn’t believe it. It didn’t feel real. I was just in shock,” Muhammad Amin Abdullah, 28, said on Wednesday.

“But when I learned that his actions saved all the kids … I felt proud, and I ​felt comfort because I know that’s exactly how my dad would have wanted to go out — protecting ​people.”

He and his brothers Jibreel and Khaled spoke to Reuters as they accepted condolences at their father’s home, describing ‌him as ⁠their best friend and a pillar of the community.

Khaled, 24, said his family has drawn strength from the way he died.

“The fact that he was on the front line, trying to defend kids and innocent people, that makes me feel good,” Khaled said. “Calling him a hero is the least we can do.”

Jibreel, ​21, described his father as “the ​kindest person you’d meet.”

“Ask ⁠anyone … they’d have nothing but good things to say about my dad,” he said. “Best dad you could ask for.”

The family urged others to honour their father ​by living with compassion and a sense of service.

“Live your life serving ​others … and just ⁠be kind to everybody,” Muhammad said. “The world would definitely be a better place if people lived like that.”

Their sister, Hawaa, made a similar plea on Tuesday. She told reporters their father “stood against any form of hate.”

Police ⁠and the FBI ​have said that they are investigating the attack as a ​hate crime but have not offered details about the possible motive of the attackers, who took their own lives shortly after the ​shooting.