Dozens were hurt in two separate bomb attacks late on Wednesday in central and southern Philippines.
A total of 32 people were injured when two improvised explosive devices were triggered with mobile phones at around 9pm on Wednesday during an amateur boxing event in Hilongos town in the central Leyte province, about 1,000km south-east of the capital, Manila.
A third improvised explosive device failed to go off and was later defused, said the police and military in a joint statement yesterday.
"It was drug-related," President Rodrigo Duterte told ANC News channel, though he also linked it to the Maute Muslim militant group seeking recognition from the Islamic State in Iraq and Syria.
He said: "Maute is rampaging now... It's being driven by drugs. They want money for their uprising. To sustain it, so they're dealing in drugs. We have a terrorism being fed with drugs."
No group has claimed responsibility for the attack but initial investigations showed that the three devices were built out of 81mm mortar shells.
This method has been linked to the Maute group, which has been blamed for the bombing of a popular night market in Davao, Mr Duterte's home city, that left 14 people dead in September.
Security officials reported another explosion on Wednesday evening in Aleosan town in North Cotabato in the Mindanao region, south of Manila.
Senior Inspector Edwin Abantes said seven people were hurt when a bomb went off as a truck passed by.
This attack occurred just 30km from Midsayap town, also in Muslim-majority North Cotabato, where a grenade attack on Saturday in front of a Catholic church left 16 wounded.
Police have speculated that this may have been again the work of the Maute group, or a retaliation by drug gangs over police crackdowns.
In a news briefing, President Duterte's spokesman, Mr Ernesto Abella, said the bombing was "an area of concern, but not alarm".
Security officials in Mindanao have been on heightened alert since early this month on reports that extremists may be planning attacks to disrupt the Christmas and New Year holidays.
Mindanao has been racked by violence perpetrated by Muslim extremists who consider the region their ancestral homeland.
Various separatist groups have waged a decades-long war that is believed to have claimed more than 120,000 lives.