A man in his 40s died Saturday after breaching security at Honolulu Airport and becoming unresponsive during a struggle with responders, an airport spokesman said.

The man initially used force to make his way through the exit of a security checkpoint at the Island Air and Mokulele Airlines commuter terminal at about 5:48 a.m., said state Department of Transportation spokesman Tim Sakahara at a news conference.

“He did manage to force his way into the secured area, but seconds later he was apprehended and taken into custody,” Sakahara said.

Before security was able to capture the man, he apparently broke through a secured door to a restricted area for ticketed passengers and employees with badges.

Sakahara said the man, who was not a ticketed traveler, was detained outside the terminal building in a walkway that leads to where the planes are parked.

It was not clear what the man’s intent was, and he did not say where he was trying to go, but he was combative and continued struggling after security detained him, Sakahara said. Multiple agencies including state deputy sheriffs, Honolulu police and Honolulu firefighters responded, and when the man became unresponsive, lifesaving measures were initiated by the fire department, paramedics and airport rescue firefighters.

The man, who was not armed and appeared to be acting alone, was taken to a hospital where he died, Sakahara said. An autopsy will be performed, and police said homicide detectives were investigating.

Sakahara said airport officials will hold debriefings to determine if improvements in response can be made, but it appeared procedures were followed.

“All security protocols were followed as directed in this case,” he said. “Everything did go as planned.”

During the altercation, a Securitas law enforcement officer sustained head injuries and remained hospitalized Saturday afternoon, Sakahara said.

Airport authorities also notified the FBI and the Department of Homeland Security about the incident.

Sakahara said checkpoint operations were suspended during the incident but resumed shortly after and no flights were delayed.

He said the top priority for airport officials is the safety of passengers and employees, and passengers did the right thing by staying calm and following instructions during the incident.

Airport procedures were not changed Saturday after the incident because it appeared to be isolated, Sakahara said.

Todd Knight, a Mokulele Airlines aircraft mechanic, said he heard the man was ramming doors to exit the terminal until one gave way. He said the doors are locked by a magnet that airline employees open to escort passengers out to the planes.

Mona, a customer service representative at Mokulele Airlines who declined to give her last name, said she was preparing a flight for departure when she heard someone yelling to call the sheriffs. Before she could find out what happened, police cars swarmed around the terminal building and fence line.

“Kind of exciting,” she said. “Nothing ever happens here.”

She said the airline had eight passengers scheduled for a flight at the time, and the passengers were able to depart on time at about 6 a.m.

“It all happened in a matter of 15 minutes,” she said. “It was real quick.”

Sakahara said security breaches at Honolulu Airport are rare. In April 2013, a homeless woman attacked a Transportation Security Administration officer before being detained by a vacationing California policeman, local media reports said.