A Texas police officer was killed and another critically injured when their helicopter crashed as they were responding to a call early Saturday, according to officials.

The officers were trapped inside the copter after it went down around 2 a.m. near an apartment complex in north Houston and had to be extracted by firefighters, FOX 26 in Houston reported.

Houston Mayor Sylvester Turner mourned the loss of the officer, who was not immediately identified.

“This is a sad morning,” Turner said in a tweet.

"They literally had to cut the pilots out of the wreckage," Police Chief Art Acevedo told reporters at a news conference soon after the crash.

The pilot who survived was "very banged up" and required immediate surgery, but Acevedo was hopeful he would recover.

"We don't have any idea why it went down at this time," the chief told reporters near the crash scene. 

No further details have emerged, and the cause of the crash remains under investigation.

KOBE BRYANT CRASH VICTIMS SUE HELICOPTER COMPANY 

The helicopter was called to assist with a search for bodies in a nearby bayou, prompted by a tip that the police chief characterized as "probably a bogus call -- we don't know."

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No other injuries were reported.

Acevedo said police alerted family members and helped transport them to the hospital.

He noted that shots rang out across the street from the apartment complex around 3 a.m., while police were investigating the crash.

Six people were taken into custody and no injuries were reported, he said, updating the number of people arrested from an intial report of three.

Acevedo stressed that police had no information indicating the helicopter was taken down by hostile action.

The Associated Press contributed to this story.