Since the attacks in the United States on September 11, there has been considerable discussion on possible links between the al-Qaida group headed by Osama bin Laden and several Islamist groups in Southeast Asia, in particular the Abu Sayyaf group in the Philippines. Some experts say there are strong links between these groups - but others disagree.

Western governments and experts on terrorism have warned recently of links between Osama bin Laden's al-Qaida group and the Abu Sayyaf group in the Philippines.

The Abu Sayyaf is fighting for an independent Islamic state in southern Philippines. It gained notoriety in the past two years after it kidnapped dozens of tourists and workers at resorts in the region. The group has released some hostages, and executed others. It continues to hold nine Philippine workers and two U.S. missionaries.

Philippine President Gloria Arroyo refuses to negotiate with the Abu Sayyaf, saying it is a criminal group.

An expert in military intelligence at the Heritage Foundation in the United States, Dana Dillon, says the Abu Sayyaf has direct ties to Osama bin Laden's network.

"Abu Sayyaf has demonstrated international reach and has already attacked locations in other countries. It has attacked in Malaysia and it has attacked in Indonesia and those are just regional," he says. "However, it also has direct links with Osama bin Ladin, al-Qaida, and has apparently supported in some way or another members of various groups that operate with al-Qaida, or various individuals that operate with al-Qaida. So yes, Abu Sayyaf has a global reach."

Abu Sayyaf's founder, Abduraja Janjalani, studied in Afghanistan and fought with Osama bin Laden during the Afghan war with the Russians. After the war, Mr. bin Laden's brother-in-law visited the Philippines to help start the Abu Sayyaf. The group split from a more established separatist Muslim group, the Moro Islamic Liberation Front.

President Arroyo's spokesman, Rigoberto Tiglao, says there is evidence of contacts between the two groups 10 years ago but he says there has been nothing since the mid-1990s.

"There's been some firm data that in the early 1990s, operatives of bin Laden managed to first, finance some of their [Abu-Sayyaf's] operations, and second, to undertake training for explosives," Mr. Tiglao said. "But that was way back in the 1990s and our intelligence report is that even the bin Laden group felt that the Abu-Sayyaf weren't really that much an internationalist terrorist group."

However, a professor of Asian studies at the University of the Philippines, Aziri Abubakar, recalls that during a kidnapping in the late-1990s, the Abu Sayyaf demanded the release of a man convicted in the first bombing of New York's World Trade Center.

"The members of the Abu Sayyaf claim that they have indeed maintained their links with rebel elements in Afghanistan or in other Muslim worlds," he said. "So there are many clear indications that from the very beginning they have links with that group."

But Professor Aziri says it is not clear whether the links include material or financial support.

The director of the Third World Studies Center at Philippines University, Mariam Coronel Ferrer, says that Abu Sayyaf's founder was killed in an ambush in 1999. After his death, she says the group degenerated into bands that survive by bombing and kidnapping. Nevertheless, she says their use of religion to justify their means remains a strong force.

"We may say that because of the methods they use, they are basically a criminal group," she said. "But still there's that potent mix of a group of criminals who justify their activities on a set of grievances and a set of beliefs that find distinction from the rest of the [Muslim] population of the Philippines."

A professor of Islamic studies at the University of Philippines, Julkipli Wadi, says there is a shared sympathy among such movements. He says there is a tension between Islamic movements, which appeal to less privileged sectors of society, and the governments of many predominantly Muslim nations. Many of those governments, he says, are seen as undemocratic and unresponsive to their people.

"The states, countries, have the Organization of Islamic Conference, so they ally amongst themselves. On the level of Islamic fronts, or Islamic movements, they have this, also, network of Islamic movements. And this is where the Abu Sayyaf could now be linked," he said.

Professor Wadi says feelings of oppression and struggle against a common, more powerful enemy can serve to unite such movements and bring them sympathy in the form of funding, organization, and cooperation.