The men, who were detained on Monday at the airport with an explosive-laden van, had planned a series of consecutive attacks, apparently to publicise their anti-China grievances, Justice Secretary Leila de Lima told reporters.
"Apparently this is a misguided group. They claim to be defenders of the Filipino people and consider China and (Filipino-Chinese) oligarch taipans' monopolistic business practices and illegal mining as enemies," she said.
De Lima said the men appeared to be particularly angry over the Philippine government's perceived "soft" stance towards China in a dispute over competing territorial claims in the South China Sea.
"They want this administration to espouse a tougher stance in this dispute with China," she said.
De Lima said the group, which may involve more people than those detained, had planned a series of attacks on Monday at buildings linked to China or the Chinese-Filipino business community.
"They also had plans yesterday to firebomb SM Mall of Asia in Pasay city and strafing the Chinese embassy and the DMCI building," she said.
SM Mall of Asia is owned by Henry Sy, the Philippines' richest man who was born in China.
DMCI is a construction firm owned by David Consunji, another ethnic-Chinese Filipino who Forbes magazine lists as the sixth richest man in the country.
Nevertheless, de Lima said investigators were not convinced that the group's real intention was to express anger against China and Chinese interests.
"We want to know how big this group is, what is their capacity really to create all this havoc, and what is their real agenda," de Lima said.
"Are they on their own or are there (people) behind them? We will investigate all these."
De Lima said the leader of the group claimed to belong to a secretive fraternity of police and military figures that had been linked to coup attempts in the 1980s that failed to topple then-president Corazon Aquino.
She said this claim had not yet been verified.
The current president is Benigno Aquino, Corazon's son, who has been an extremely popular president during his four years in office but has endured a few months of brutal political battles over a series of controversies.
A senator-ally of Aquino alleged in July that retired military officials were trying to recruit troops to destabilise the government.
The military reaffirmed its loyalty to Aquino following the senator's comments.