Meanwhile, missionaries Martin and Gracia Burnham of Wichita, Kan., held hostage by Muslim rebels for over nine months, have been seen with their captors on a mountainous village on southern Basilan island, a local official said on Thursday.
"They were in good condition, under the circumstances, when they were seen last week by my informants," Maluso mayor Sakib Salajin told reporters in the Isabela capital town.
It was the latest of a series of sightings of the Burnhams in recent weeks on Basilan, a jungle-clad stronghold of the Abu Sayyaf guerrillas, whom the United States has linked to the al Qaeda network of Saudi-born dissident Osama bin Laden.
Senior Supt. Bensali Jabarani, police chief of the southern island province of Basilan, said his men arrested the four men and four women accused of aiding the kidnappers who hold the Burnhams and Filipino nurse Ediborah Yap.
About 160 U.S. Special Forces are on the island training Filipinos to fight the group, which has been linked to al Qaeda.
The suspects were charged with murder but it's not immediately clear whom they are accused of killing.
In a video obtained by Reuters on Thursday, Martin Burnham said his captors were targeting not only Americans but also Europeans and other Westerners because of U.S. policies in the Middle East.
The video showed the Burnham couple to be in relatively good health and did not have the haggard look they wore in a previous video shown on local and U.S. television in November.
It was not possible to determine when the video was shot.
The informants, who supplied the video but declined to reveal their identities, claimed the couple was filmed in mid January. Some people who saw the video said they thought it might have been taken earlier than November, judging from the couple's appearance.
The mayor of the Basilan town of Maluso, Sakib Salajin, said the arrests were to pressure guerrillas to surrender or release their hostages.
"If we get their wives, their resolve will weaken because our planning is to mentally torture (the rebels)," said Salajin, who said he helped plan the arrests. His security staff detained the suspects late last month.
From the provincial jail in Isabela, the suspects denied any involvement with the Abu Sayyaf and said they were not aware of any charges against them.
In the video, three hooded gunmen stood behind the Burnhams as Martin read a statement believed to be written by his captors, who claim to fight for an independent Muslim state in the south but whose main activity is kidnap for ransom.
Martin wore the same T-shirt he was wearing in the footage taken in November, but looked much healthier and relaxed, with a shorter beard and without glasses.
Gracia, sitting next to him, did not speak on the video but at one point rolled her eyes as her husband read the statement. She also appeared to be wearing the same dark blue T-shirt shown in the November video but also looked less haggard.
She did not have the Muslim scarf she had worn in the November footage. Some of those familiar with Abu Sayyaf behavior say the hostages come under increasing pressure to wear the veil the longer they are held captive.