Police say the blast occurred when the bus was traveling near Cotabato City on Mindanao Island, where armed groups are active.
A child has been killed and six others injured after a bomb exploded on a public bus in the rebel-ridden southern Philippines.
Police said the blast occurred Tuesday when the bus was traveling along a highway near Cotabato City on Mindanao Island, a refuge for several armed groups ranging from communist rebels to religious fighters.
The bomber struck shortly after noon in front of a police recruiting center at Kisak, west of the city, according to Randy Hampac.
A five-year-old boy was killed in an explosion that shattered the rear windows, Hampac said. The wounded included a five-month-old baby and a three-year-old child.
A police report said one of the victims saw a male passenger leave “luggage” on the bus as he got out and it later exploded.
Regional military spokesman Lieutenant-Colonel John Baldomar said no group had acknowledged that they had carried out the “suspected attack”.
Attacks on buses, Catholic churches and public markets have been a feature of decades of unrest in the region.
Manila signed a peace treaty with the country’s largest rebel group, the Moro Islamic Liberation Front, in 2014, ending their deadly armed rebellion.
But smaller groups of fighters opposed to the peace deal remain, including fighters who profess allegiance to the ISIL (ISIS) group. Communist rebels also work in the region.
In May 2017, hundreds of pro-ISIL foreign and local armed men seized Marawi, the country’s largest Muslim city.
The Philippine army returned to the devastated city after a five-month battle that killed more than 1,000 people.