MANILA, Philippines — A suspected robbery gang armed with automatic weapons and grenades fired on Philippine police officers who were tailing them, leaving at least 16 people dead in a fierce shootout in a Manila suburb, officials said Saturday.

Officers were following the suspects when the gunmen sensed the surveillance and opened fire, triggering the gunfight late Friday near a residential subdivision in suburban Paranaque city, metropolitan Manila police Chief Leopoldo Bataoil said.

He said the suspects, some armed with M-16 rifles fitted with grenade launchers, thought they had been cornered and fired at everyone in sight.

"When they found out they were being trailed ... they went berserk," he said. "They fired all around, including at a flammable tanker beside a warehouse."

Among those killed were 12 suspected gang members and a police officer. Three people nearby, including a man and his 7-year-old daughter in a car passing through the area, were also killed.

Police initially reported that five civilians were killed, but two turned out to be gunmen whose bodies were dumped on the road, said national police Director General Jesus Verzosa.

Three police officers were also wounded, including one who was in critical condition, Bataoil said.

'Underestimated the firepower'
He said at least three of the gunmen were able to escape in a car they commandeered after firing a grenade at a gatehouse at the entrance to the residential subdivision, wounding two guards.

"I think that my men underestimated the firepower of the suspects," Verzosa said.

Bataoil said investigators believe the assailants belonged to a violent gang whose members have posed as police officers, adding that two of the slain gunmen were found wearing police-style bulletproof vests.

The group has been blamed for killing a bank teller and two guards for an armored truck picking up money from a bank on the University of the Philippines campus last month.

Bataoil said he has ordered an investigation into the deaths of the civilians.