A man barricaded himself inside a bank in the southern California city of Bakersfield with an unknown number of people, police said on Tuesday.

The unidentified man had a bomb strapped to his body, according to Bakersfield Now.

Police responding to a call of a bomb threat arrived at the Chase bank building in downtown Bakersfield at about 1pm, Sgt Eric Celedon of the Bakersfield police department told the ABC affiliate 23ABC.

“I’m not using the H word,” Celedon said, when asked whether the man had taken hostages. “However, there is an unidentified male subject in there with an unknown number of our community members and they’re refusing to come out at this point.”

Hours later, Celedon publicly acknowledged the situation was indeed a hostage crisis.

“With the cooperation of our crisis negotiation team and the assistance of the FBI negotiations team, we were able to negotiate the safe surrender of one of the hostages,” Celedon told reporters, according to NBC News. The remaining hostages were “in good health”, he added.

The officers remain in contact with the man inside the bank by phone, KCRA 3 reports.

The city also issued evacuation orders in the area, according to Fox 11 Los Angeles.

“Please stay out of the downtown area,” the Bakersfield police wrote on social media. “Road closures are in effect and will remain in effect until further notice.”

A JPMorgan Chase spokesperson, Peter Kelley, said the bank was working with law enforcement and its “focus is on the safety of everyone involved”. He provided no other details.

Several city buildings were placed on lockdown, including city hall north, city hall south, the development services building and Bakersfield police headquarters.

About a dozen police cars were on scene along with one tactical vehicle and multiple emergency responders, according to media reports.

Bakersfield, a city of about 380,000 residents, is the county seat of largely rural Kern county and is about 100 miles (160km) north-east of Los Angeles.