Three police officers and three soldiers were among 13 armed people killed during a shootout with security forces in a street in Quezon City in the Philippines.

Two of the soldiers were carrying military intelligence identification, a report by The Philippines Star newspaper said.

The men, including alleged gambling czar Victorino Siman, who operated mainly in the southern area of Luzon, the largest Philippine island, were killed in two sport utility vehicles.

Police said the vehicles ran a military checkpoint around 3 p.m. after refusing to allow security personnel to search the vehicles. Police officers and soldiers opened fire, leaving the vehicles riddled with bullets from the 10-minute exchange.

Police launched an investigation into the shootings in which many of the dead had been shot in the head, the Philistar report said.

Investigators are looking into reports that the dead men were acting as bodyguards for Siman and members of his business.

Police suspected the vehicles were carrying up to $2.5 million from illegal gambling operations in the Tagalog and Bicol regions of Luzon, although no cash was found, the Philistar report said.

Siman was suspected of running guns and police said they recovered eight .45-caliber pistols, a baby Armalite and an M-14 rifle from the vehicles.

A report by ABS-CBN News said Siman and another companion who died in shooting -- Mimaropa police chief of operations superintendent Alfredo Perez Consemino -- were business partners in a security agency.

The checkpoint had been set up because of a tip received by police that the group would be in the area for a meeting regarding illegal gambling businesses, ABS-CBN said.

Jueteng -- a numbers game -- is illegal in the Philippines but has proved virtually impossible to stamp out over the decades.

Soon after being elected in mid 2010, President Benigno Aquino III said he wouldn't legalize the multimillion-dollar numbers game played clandestinely but widely by rich and poor throughout the country.

It was jueteng that led to the downfall of former President Joseph Estrada, who sought re-election but lost to Aquino, a report by GMA News said in 2010.

Estrada, in 2000, was accused of receiving millions worth of kickbacks from jueteng operators, allegation he repeatedly denied. After being detained for six years, he was convicted of plunder in September 2007, but was given presidential pardon a month later, GMA said.

Jueteng is "embedded in local culture" because it has the support of local communities, a report by the Philippine Center for Investigative Journalism said.

A "cobrador" knocks on people's doors to solicit bets and winnings also are delivered straight to their homes by the same cobrador.

"Jueteng aficionados are the next-door neighbor, the sari-sari store retailer, the tricycle mechanic, etc," the report said. "Villagers shell out spare change to aid the neighborhood cobrador who engages in jueteng to make ends meet."

A major appeal is that people see their community winning money.

"Winning in jueteng, unlike other forms of gambling, is tangible. One's next-door neighbor wins, not someone from a distant province announced over the radio," the report said.