HOUSTON — Two suspects are dead after a shooting on Monday that injured five Houston police officers, including four who were hit by gunfire as they attempted to serve a search warrant at a home where drug selling was suspected, the police chief said.

A group of about a dozen officers with the Houston Police Department's narcotics unit were attempting to serve the warrant when they forced open the home's front door and immediately faced gunfire from one or two individuals, said Police Chief Art Acevedo.

Police targeted the southeast Houston home following an investigation that began after officers got a tip from a neighbor that black tar heroin was being sold from the house, Acevedo said.

"Once the officers breached the door and the gunfire began from the suspects, one of the suspects actually retreated momentarily to the back of the room and then that suspect came back and again engaged the officers in gunfire," Acevedo said at a Monday evening news conference.

It was not immediately known how many officers returned fire but the two suspects were later found dead after SWAT officers used two robots to go into the home and determine that it was safe to enter after the gunfire stopped.

All the officers were taken to Memorial Hermann-Texas Medical Center in Houston, with two of them transported by helicopter.

Four officers were shot, with two being hit in the neck. Those two officers underwent surgery and were in critical but stable condition, Acevedo said.

"We're hopeful that they will recover," Acevedo said of the two critically injured officers.

The other two officers who were shot were in stable condition and were able to walk around, Acevedo said. Police later said that one of those officers was released after being treated for a gunshot wound to the shoulder, and that the other remained hospitalized in good condition.

A fifth officer suffered a knee injury during the shooting and was also in good condition.

Acevedo didn't immediately have additional information about the suspects. The names of the injured officers were not immediately released.

"This has been a tough day for our city," said Houston Mayor Sylvester Turner. "Pray for (the injured officers) and pray for their families." Texas Gov. Greg Abbott said in a statement that the shooting was a "solemn reminder" of the service and sacrifices made by officers.

AP