"It’s back to full offensive mode," military spokesman Lt. Col. Daniel Lucero said in an interview.
Malacañang, however, may extend the shaky truce if recommended by security advisers, presidential spokesman Ignacio Bunye said.
Military operations are expected to intensify to prevent the NPA from extorting so-called revolutionary taxes from election candidates in exchange for safe passage, which they do every election.
An estimated P200 million were collected by the NPA from politicians in the 2001 elections, according to the military.
President Arroyo has earlier ordered military operations to stop the extortion.
"The military is going on full offensive operations against the rebels to ensure that candidates will not be deprived to campaign in places they like to go or visit," Lucero said.
The military declared a ceasefire against the estimated 8,500-strong New People’s Army (NPA) on Dec. 10 in the spirit of the holiday season, as it has been its practice in the past.
The NPA responded with its own unilateral ceasefire on Dec. 20 which ends today.
The rebels violated its own truce, however, when, on New Year’s eve, communist hit men executed Cpl. Alfredo Monacho in Samar. One of Monacho’s two young children were also killed when they embraced their father to shield him.
"The brutal killing of a soldier in Samar attests to this treacherous nature of the NPA," Lucero said.
The Communist Party of the Philippines (CPP) has been waging a decades-long insurgency through its armed wing, the NPA. — With Marichu Villanueva