Weary search teams recovered another 14 bodies from Guinsaugon, a farming village where up to 1800 people died when they were buried in mud up to 10m deep on Friday.
Five people were killed in a landslide elsewhere in the Philippines.
The hunt for survivors focused on the school, after unconfirmed reports circulated that some of those inside
sent text messages to loved ones after an adjacent mountain collapsed following two weeks of heavy rains.
Ian Degamo, with an aid group called Maayo, was digging there with about 15 other volunteers aided by two sniffer dogs from the Red Cross.
"The dogs smelled something. We started to dig, but there was nothing," Degamo said.
A damage assessment team of up to 30 armed US marines based in Okinawa, Japan, visited Guinsaugon, a village where most of the population of more than 1800 people were feared buried beneath a massive pile of mud and debris.
More than 30 US marines then joined the search around the school, digging through the night with flashlights.
They were part of a 1000-strong marine contingent on the USS Essex and the USS Harper's Ferry who recently arrived for joint military exercises and were diverted at the Philippines' request.
The confirmed toll was 72, but hopes of finding survivors were fading quickly.
Unidentified victims are buried
at a public cemetery
Five people were killed on Saturday night when another landslide swamped two houses in Bayog town in Zamboanga del Sur province, hundreds of kilometres away, said Major Gamal Hayudini of the military's Southern Command.
A women was pulled out alive with a broken leg.
Officials held a mass burial for 50 unidentified bodies that were decomposing quickly in the tropical conditions.
Lieutenant Colonel Raul Farnacio said searchers were focusing on the buried elementary school, but that teams using police search dogs were also digging around the village hall, where about 300 people had been attending a women's conference.
"All the efforts of our government continue and will not stop while there is hope to find survivors," said Gloria Macapagal Arroyo, the president.
"The nation is grateful for the continued prayers, concern and help from our world allies."
Arroyo says government efforts
will continue to find survivors
Referring to residents' claims that illegal logging contributed to the tragedy, Arroyo said: "Let us link arms to preserve our environment and protect what remains of it for our next generation."
Rescue workers treaded carefully to avoid becoming casualties themselves as the uneasy mud settled.
A no-fly zone was established over the disaster area out of fears that powerful downwinds from helicopters could dislodge the mud.
Rescue workers shouted and banged on boulders with stones in the hope that survivors would hear.
There was only silence.
Survivors and relatives of the missing had trouble figuring out where houses once stood. The area has been drenched by 68cm of rain over the past two weeks.
Officials said 57 people were plucked alive from the mud on Friday, but on Sunday the figure was lowered to 20. There was no immediate explanation for the discrepancy.