DAVAO CITY, Philippines -- As many as 13 people including six children were wounded when two unidentified men hurled grenades into two houses in Butuan, military and Red Cross officials said Saturday.

The men threw two grenades into the homes of the Eranon and Lampona families in a suburb of Butuan City late Friday and then sped away on their motorcycle, said military spokesman Major Randolf Cabangbang.

The Philippine Red Cross said 13 people were wounded. Cabangbang said six of these were children.

The attack is believed to be linked to a family feud between Muslim clans in the south, Cabangbang said. Such feuds are often exacerbated by the prevalence of weapons in the south where various armed groups are active.