ZAMBOANGA CITY -- Two wives of Abu Sayyaf leader Albader Parad and four others were arrested at a checkpoint, three hours after Tuesday's bloody explosion in Jolo, the military said.

Navy spokesman Lieutenant Colonel Edgard Arevalo said those arrested were accused of aiding the al-Qaeda-linked bandits' kidnapping activities in Sulu province.

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The six were Rowena "Honey" Aksan and Nursima "Simang" Annudden - Parad's first and third wives, respectively; Rabia Polalon Asiri and Marwina Salasain, wives of Alvin Bagadi and of Alhabsy Misaya (both men are urban terrorism and demolition experts), respectively; Madrimar Bagadi, Alvin's brother; and Midsfar Aksan, Rowena Aksan's bother.

Arevalo said they were arrested around 11 a.m. Tuesday at a checkpoint in the village of Tagbak, Indanan, Sulu.

The navy spokesman said Aksan was identified to have allegedly taken part in the kidnapping of Red Cross workers Filipino Mary Jean Lacaba, Swiss Andreas Notter, and Italian Eugenio Vagni last January 15.

She was also seen inside the bandits' camp taking care of Lacaba.

Those arrested are suspected to have provided logistical and service support in terms of vehicles, purchase, and delivery of food to the Abu Sayyaf rebels.

"They did not resist arrest," said Arevalo of the six suspects.

Found in their possession were cellular phones and three bundles of cash at P100,000 each.

Tuesday's arrests came hours after a motorcycle bomb blast, which was blamed on the Abu Sayyaf, that killed two people and wounded 31 others in the provincial capital, Jolo.

"The group later underwent questioning as to their possible involvement in the bomb blast. There is reason to suspect that the cellular phones caught in their possession could be part of the triggering mechanism that set off the bomb that was placed in the motorcycle that exploded at Go Tek Leng Hardware," the official said.

The military said the explosion might have been a diversionary tactic to relieve the pressure on gunmen still holding one ailing Red Cross hostage, Italian Eugenio Vagni. The two others have been released.

The Marines, in coordination with the Philippine National Police, are set to file appropriate charges before the Jolo Regional Trial Court Friday, Arevalo said.

The Abu Sayyaf and its allies have turned to kidnappings to make money in recent years, raising concerns among Philippine and US security officials that ransom payments could revive the group, which has been weakened by years of US-backed offensives. (VR/Bong Garcia/AP/Sunnex)