The bomb was allegedly planted on a motorcycle taxi parked outside the shopping mall in Cotabato City, where people were buying New Year gifts, according to the newspaper Mindanao Examiner.
No terrorist group has so far claimed responsibility for the attack. Meanwhile, Mayor Frances Cynthia Sayadi has reportedly labelled the blast a "terrorist act".
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The blast comes days after the Congress of the Philippines approved the third extension of martial law in Mindanao over a persistent security threat in the region.
Martial law was initially declared in Mindanao in May 2017 after the conflict broke out between the Philippine security forces and extremists affiliated with the Daesh* terrorist group, including the Maute and Abu Sayyaf jihadist groups.
*Daesh (also known as ISIS/IS/ISIL) is a terrorist group banned in Russia.
