A spokesman for the group made the statement in a call to a radio station in Mindanao after police defused two more bombs in Makati and Pasay cities over the weekend, bringing to 13 the number of bombs found in Metro Manila and other key cities since March 18, Reuters news agency reported.
"We will continue planting bombs. Just observe what happens in the coming days," a person named "Adrev," who claimed to be a spokesman for the group, told the station affiliated with Radio Mindanao Network.
The name "Adrev" was also used in statements found inserted in the eight ordnance packages which, police said, contained genuine bombs but were not rigged to explode.
The group claimed it planted the eight bombs in Metro Manila while groups with similar names claimed to have earlier planted five other bombs in Cotabato City and General Santos cities.
Police said the explosives, which Palace spokesman Rigoberto Tiglao described as "crackpot" bombs, were not meant to hurt people but only to draw attention to a political statement.
In their statement, Adrev said their group demanded federal rule for indigenous peoples, Christians and Muslims.
In the latest finds in Makati and Pasay cities, a street sweeper, whom authorities identified as Rissa Reyes, 46, supposedly found a brown envelope with protruding wires at the foot of the pedestrian overpass near the Philtranco bus terminal along Epifanio de los Santos Avenue (EDSA) in Pasay City.
Bomb disposal experts said the package contained two hand grenades rigged to a clock with some batteries and a plastic container filled with unspecified blue powder.
On Friday, pedestrians found two brown envelopes abandoned at the pedestrian overpass along EDSA near Estrella street in Makati City.
Police said one of the envelopes contained two hand grenades rigged to a digital clock with a soda can filled with unspecified blue powder. The other package contained 46 rounds of 5.56 mm ammunition and copies of a statement from the IPFSA.
Police said none of the explosive devices found so far were intended to kill but were apparently meant to scare people and send a political message.
The other devices discovered this week were planted near some railway stations, abandoned in a jeepney in Caloocan City and near street sidewalks in Makati City.
National Capital Region Police Office (NCRPO) chief, Director Edgar Aglipay said the MRT cameras also captured the image of a third man but police have not released his sketch.
"We will continue to guard as many areas as we can so that in the end we hope to be able to apprehend those who are planting these bombs," Aglipay said in a televised interview.
"We are zeroing in on three groups which we cannot disclose right now," he added, stressing the authorities are not discounting the possible involvement of other groups.
Philippine National Police (PNP) chief Director General Leandro Mendoza earlier tagged renegades of the Moro National Liberation Front (MNLF) and the Moro Islamic Liberation Front (MILF) as the ones responsible for the bombs.
Police intelligence officials, who requested anonymity, said this theory was bolstered by two-month-old intelligence reports that new MILF recruits would be sent to Manila to stage bomb attacks.
The officials said most of the members of the IPFSA came from the two Muslim separatist groups but the others were from the little-known People’s Communist Party (PCP), supposedly a splinter group of the Communist Party of the Philippines-New People’s Army (CPP-NPA).
The PCP is said to be led by a certain Ike delos Reyes, supposedly a former ranking official of the communist Revolutionary Proletarian Army-Alex Boncayao Brigade.
"So far these bombs were really intended for some crackpot impact. We don’t think they are really threats to security," Tiglao said.
He said the Arroyo administration is not considering the bomb scares as a national security concern and has decided to leave the matter to the police and military.
While Tiglao said the bomb scares cannot be considered as part of a organized destabilization threat, he admitted that the impact of such "headline-grabbing" incidents can really be jarring to the country’s image of political stability before the international community.
"This is what is really saddening here in our country. There are really some attempts to bring down this country when we have already normalized... There are really desperate or crackpot actions," Tiglao said.
Tiglao made the remark amid reports that London has issued an advisory to British citizens against travel to the Philippines.
Tiglao also dismissed the concern of pro-administration Sen. Joker Arroyo that the bomb scares were part of a right-wing conspiracy meant to justify the imposition of martial law in the country.
"There’s no truth to that. We don’t need martial law today. We cannot return to martial law and we cannot say that it’s the police behind these," Tiglao said.
Defense Secretary Angelo Reyes dismissed as "preposterous" accusations that the bomb scares were orchestrated by the military as a precursor to a declaration of martial law.
"It is unbelievable,’ Reyes said in an impromptu press conference at the Philippine Military Academy (PMA) in Baguio City. "Why would the government want to do that?"
Reyes said the priority of the government is to improve and enhance the climate of confidence in the administration, the peace and order situation and the country’s investment climate.
"These bomb scares are not doing that," Reyes stressed, blaming instead groups that would benefit from a perception of instability. "They don’t want investments to come in." - Jaime Laude, Marvin Sy, Nikko Dizon, Marichu Villanueva Artemio Dumlao