A man and a woman are dead and 28 others have been injured in a bomb blast outside a shopping mall in the southern Philippines.

A crude bomb, blamed by security forces on a small pro-IS militant group, has killed two people and wounded dozens in the southern Philippines.

Islamist militants operate in the south of the largely Christian Asian country and some are known to have links with groups abroad, including al Qaeda and IS.

Major General Cirilito Sobejana, an army division commander, told Reuters the bomb bore a "Daesh-inspired signature", referring to IS by another name.

The bomb went off at the entrance to a shopping mall in the city of Cotabato in Monday's early afternoon. As well as the two people killed, 28 were wounded, he said.

A second bomb was recovered in the same area, he said.

Sobejana said he suspected the blast was retaliation for the killing by government troops of seven members of a small militant group that has pledged allegiance to IS.