MANILA, Philippines—The political rivalry between the Nograleses and the Dutertes are heating up, with members of the two families expected to slug it out for two important posts in the 2010 polls after Speaker Prospero Nograles formalized his bid on Saturday to run for mayor of Davao City.

Nograles filed his certificate of candidacy for Davao City mayor on Saturday, and he is expected to go up against the incumbent Mayor Rodrigo Duterte's daughter, Sarah, the incumbent vice mayor.

Nograles' son, Karlo, is going to run for his father's old post, and is expected to go up against the elder Duterte.

Speaker Nograles said his platform of governance as Davao mayor would focus on putting a stop to summary executions, to which the incumbent mayor has been linked.