Authorities put the country’s premier airport on full alert after the twin bombings in Quiapo, Manila, which an international security analyst warned could be test runs by the Islamic State for wider attacks during the Ramadan.

Police had earlier played down an IS claim that it was behind the Quiapo bombings, saying they did not have the characteristics of a terrorist attack.

Airport Police Department Gen. Romy Labador said all airport policemen were placed on alert status as additional officers were deployed inside and outside all terminals of the Ninoy Aquino International Airport in Pasay City.

The Philippine National Police said the twin explosions in Quiapo district in Manila late Saturday that left at least two people dead and six others injured, did not constitute a terror attack and was aimed at a particular imam.

But Rohan Gunaratna, head of the International Centre for Political Violence and Terrorism Research, said the ISIS news agency, Amaq, which claimed that the IS was responsible for the explosions in Quiapo, has never issued false claims. “Amaq will exaggerate. Amaq will get its numbers and figures wrong. But we have never come to an instance where the ISIS official media has falsely claimed attacks,” he told the ANC news channel.

Gunaranta said the Philippine government must immediately arrest the people responsible for the blasts; improve knowledge on ISIS operations abroad; and work closely with authorities overseas.