An explosion rocked Datu Odin Sinsuat town in Maguindao an hour after polling centers opened on Monday morning.
The latest election violence to hit the province occurred at 7:20 a.m. in Barangay Poblacio Dalican.
It was the same area where a fragmentation grenade exploded at 1 a.m. near the municipal hall.
Authorities have cordoned off the area as they continue to conduct post blast investigation.
No one was injured in both incidents.
The blasts did not deter voters from heading to their assigned polling precincts to cast their votes.
Police say they will beef up forces to further tighten security in the area.