At least 16 people were hurt in a grenade explosion that took place outside a Catholic church during Christmas eve mass in the Philippines.

So far, no group has claimed responsibility for the attack, according to Fortune. However, Muslim rebels and Islamic extremists are known to be active in the area, which is situated in the southern island of Mindanao.

Bernardo Tayong, Midsayap town police chief, said many of the blast victims were parishioners standing outside the Sto. Nino parish church in Midsayap town, North Cotabato.

A Christmas nativity mass was being held by the Oblates of Mary Immaculate congregation when somebody hurled a grenade, trigerring an explosion just outside the church. When they heard the blast, the parishioners panicked as they rushed out, the police said.

"There was no more concluding prayers as there was a commotion," said Father Jay Virador. "People hurriedly left the church."

One of the victims was a police officer who was standing near his patrol car where the grenade exploded. The police vehicle was parked about 30 metres from the church entrance.

Even though bomb experts have already surveyed the site, the details of the attack still remain "sketchy," authorities said. Investigators discovered another improvised bomb in the area, which thankfully did not blow up.

Meanwhile, the Midsayap municipal peace and order council believes that the police might have been the target of the grenade attack. The grenade was hurled from a distance by one of two men riding a motorcycle in tandem, according to the Philippine Star. The grenade landed on the patrol car's hood and fell on the concrete pavement before going off, wounding 16 people.

Tayong said they have enlisted the help of barangay chairmen in Midsayap to help them identify the group responsible for the bombing. Local officials have also urged residents to come forward with any information that might lead to the suspects' arrest.