SAN FRANCISCO (KCBS) – The owner of a California-based bunker business said his phone is ringing off the hook, amid heightened tensions between the United States and North Korea.

Fear sells, and Ron Hubbard knows this firsthand as president of Los Angeles-based Atlas Survival Shelters. Hubbard’s company builds 20 different types of shelters, ranging in price from $10,000 to $10 million.

Interest in shelters has gone up after President Donald Trump threatened “fire and fury” at North Korea as Kim Jong Un’s regime continues testing its missile program.

“I take that as a preemptive nuclear strike,” Hubbard said.