COTABATO, Philippines - Seven people, including five children, were critically wounded in a grenade attack in the restive southern Philippines Monday, police said.

Unidentified attackers lobbed a grenade into the home of suspected drug pusher Kentia Sampulana in Cotabato city on Mindanao island minutes after he arrived, city police director Senior Superintendent Willie Dangane said.

Seven people were seriously wounded in the attack, five of them children, Dangane said.

He said police suspect that illegal drugs or a family feud may have been the motive for the attack. Sampulana, he said, was wanted for drug pushing in the area.

Revenge killings and blood feuds are also common in many parts of Mindanao, where illegal firearms proliferate and Islamic militants are known to operate.