(CNN) -- Gunmen opened fire on a local mayor and his supporters as they campaigned in southern Philippines, killing 10 people and wounding nine others, authorities said Friday.
The ambush late Thursday targeted a truck carrying Mayor Abdul Malik Manamparan and about 50 supporters, said Diosdado Alarcon, a senior police officer from Lanao del Norte province.
It left the mayor and his supporters wounded, and killed his daughter, police said.
Authorities have no suspects or motive in the attack, and an investigation is underway
The attack in Nunungan town is the latest in a string of violence leading up to the local and legislative elections on May 13.
Earlier this week, the mother of former Vice President Teofisto Guingona was ambushed and two of her civilian guards killed.
It is unclear whether the attacks are linked, but violent attacks often mar elections in the nation.
The government imposed a 150-day gun ban from January to June to curb violence during the election period, according to the national police.
Since imposing the ban, police have arrested 2,735 people for possession of weapons, ammunition or explosives, it says.