The military command said the soldiers aboard had the rank of private and were being deployed to their battalions.
The plane had attempted to land at Jolo airport, but overshot the runway without touching down. It failed to regain enough power and height and crashed at nearby Patikul.
“A number of soldiers were seen jumping out of the aircraft before it hit the ground, sparing them from the explosion caused by the crash,” the Joint Task Force Sulu said in a statement.
It was not immediately clear how many jumped or whether they had survived.
Photos of the crash site released by the Joint Task Force-Sulu showed the damaged tail and the smoking wreckage of the fuselage’s back section laying near coconut trees.
Images published by local media outlet Pondohan TV on its Facebook page showed the wreckage engulfed in flames and a plume of thick black smoke rising above houses located near the site.
Jolo airport has a 1,200m runway that usually takes civilian turboprop flights though occasionally some military flights, according to a Civil Aviation Authority of the Philippines spokesperson.
Jolo island, part of the Sulu archipelago, is about 950km south of the capital, Manila.
The army in the sprawling Philippine archipelago has been fighting a long war against Islamist militants from Abu Sayyaf and other factions.
“They were supposed to join us in our fight against terrorism,” said Commander William N Gonzales of Joint Task Force Sulu.
The Lockheed C-130H Hercules aircraft, with registration 5125, had only recently arrived in the Philippines.
It was one of two aircraft provided by the US government through the Defense Security Cooperation Agency, a government website said in January. It quoted an air force spokesman as saying the aircraft would boost capability for heavy airlift missions.
Senator Richard Gordon said it was the fourth military aircraft accident this year with “mass casualties”.
“Are we buying defective crafts… (with) the people’s money?” he tweeted.
Lorenzana said the previous mishaps were being probed and dismissed speculation about the causes as “disrespectful” to victims and their families.
Presidential spokesman Harry Roque described the accident as “very unfortunate”.
The US offered “deep condolences,” national security adviser Jake Sullivan said in a statement released by the White House.
“We stand shoulder to shoulder with our Philippine allies at this difficult time and are ready to provide all appropriate support to the Philippines’ response effort,” he said.
