MANILA - A military spokesman on Tuesday linked the Abu Sayyaf group to an explosion at a checkpoint in Lamitan, Basilan that killed 10 people.

Armed Forces spokesman Col. Edgardo Arevalo said initial reports revealed that the man driving the van that was loaded with explosives was part of the group of Abu Sayyaf leader Furuji Indama.

"I have spoken to [Western Mindanao commander Lt. Gen. Arnel] Dela Vega. Ayon sa kanya, this person whose name and identity is not known yet is part of the group of Furuji Indama," he said in a press conference.

Arevalo said they have received intelligence reports that the Abu Sayyaf group will be delivering explosives throughout Basilan, prompting authorities to set up checkpoints.

He said the explosives in the van could be a part of Indama's desperate attempts to disturb peace in Basilan, as his group is "swiftly losing ground" with a lot of Abu Sayyaf fighters surrendering.

"This group of Indama is losing ground, swiftly losing ground. That's why they are resorting to these desperate moves to disrupt the mass surrender of Abu Sayyaf in Basilan and Sulu," he said.

The military official also rejected speculations that the blast was done by a "lone wolf" attacker or a foreign terrorist as no evidence would back these claims.

Among the people who were killed in the explosion were one soldier, 5 members of the Citizen Armed Force Geographical Unit and 4 civilians.

Authorities are still verifying if the driver of the van was among those killed in the explosion.

Editor's Note: The military has clarified that only 10 people died in the July 31 explosion in Basilan. We are updating our story to reflect the new figure.