Sgt. Richard Bratz of the Delaware State Police issues a statement about the prison guards who were taken hostage by prison inmates at James T. Vaughn Correctional Center in Smyrna, Delaware, U.S., February 1, 2017. Reuters/Doug Curran A tense standoff was underway at a Delaware maximum-security prison Wednesday night as inmates took control of a building and held corrections officers hostage.

Department of Correction response teams and state police were responding to the situation at James T. Vaughn Correctional Center in Smyrna, according to Wilmington's News Journal. Emergency responders from Pennsylvania were also at the scene, an NBC affiliate reported.

"The inmates have taken over a building," said Rep. William Carson, a state lawmaker and member of the Delaware House Corrections Committee, according to the News Journal earlier Wednesday.

Four corrections department employees were taken hostage, department commissioner Perry Phelps said at a press conference Wednesday evening. At around 2:30 p.m., one of the hostages was released and sent to a local hospital with non-life-threatening injuries. Another hostage whose condition was unknown was released around 8 p.m., leaving two hostages inside the prison.

Additionally, 27 inmates were released, said Robert Coupe, head of Delaware's safety and homeland security department.

Details of the situation were scarce, but officials said it began when an officer radioed for immediate assistance in the prison's C building around 10:30 a.m. Wednesday. The building houses more than 100 inmates transitioning from maximum security to medium security.

One of the hostages, apparently reading from a script, relayed prisoners' demands in a phone call to the News Journal made from inside the prison. The hostage, who did not give his name, said "there's a lot of them" and "they got my face covered" before the call was cut off.

In another phone call posted to the News Journal's website, a voice could be heard demanding better conditions for inmates and criticizing President Donald Trump. Officials declined to comment on the recordings.

"Once this matter is resolved safely, then that will be the time to talk," Coupe said.

Firefighters rushed to the scene after receiving reports of smoke, and were being held on standby, according to the Associated Press. Helicopters could also be seen over the prison.

All state prisons were put on lockdown, per Department of Correction policy, multiple sources reported, although Department of Correction spokeswoman Jayme Gravell said the situation provided no threat to the public.

The prison — the largest in Delaware — houses 2,500 inmates, according to a government website.

At the press conference, Delaware Gov. John Carney said he spoke with families of the hostages.

"Our focus throughout the day has been the safety of our corrections employees," he said.