Two Communist fighters were killed by government troops during an attack on a convoy carrying vital aid to stricken survivors of typhoon Haiyan, said reports.
Fighting broke out 250 miles south of the capital city Manila when trucks and lorries were ambushed by the new People's Army - which is the armed wing of the Philippines Communist Party.
Lieutenant Colonel Joselito Kakilala told AFP Agency: "There were no casualties on the government side. We thwarted the plan of the rebels to ambush a government relief convoy."
The Philippines Communist Party denied attacking an aid convoy and claimed government troops had been ambushed while carrying out a search and destroy mission against the CPP.
A spokesman said: "The Aquino regime and the AFP (Armed forces of the Philippines) are lying through their teeth in claiming that their troops involved in an armed encounter yesterday were involved in a humanitarian mission, exploiting the plight of the Yolanda disaster victims to conceal the brutalities of their continued offensive operations."
"The encountered AFP troops were clearly on an offensive mode and carrying out search and destroy operations in the interior areas of Matnog."
The Communist insurgents claimed its forces had been trying to get help to people in remote areas such as Samar and the Leyte Islands.
Elsewhere, 150 government troops are patrolling streets in the city of Tacloban, which was almost completely flattened by Typhoon Haiyan. The military presence is a bid to halt looting which has broken out in some areas.
Philippines Interior Secretary Max Roxas said: "We are circulating them in the city to show the people, especially those with bad intentions, that the authorities have returned."
Manila police officer Julian Bagawayan said 150 members of his riot police squad were flown to Tacloban to enforce a nighttime curfew that began Monday.
"Our mission is to help the police of Tacloban because they are also victims. We all know the government is down. We came here to help the government," he told AFP.
"We are here to stop people looting properties and breaking into homes."
Elsewhere in the Talcoban mourners were scattered by gunshots during a mass burial.
Tacloban mayor Alfred Romualdez said: "We had finished digging the mass burial site. We had the truck loaded with bodies but there was some shooting. They could not proceed."
A further 10 people died amid the continuing chaos after they were struck by falling sacks of rice.