By Kate McGeown BBC News Online

The attackers took part in an almost suicidal mission

Mystery surrounds the identity of the attackers - and the reason for what many see as little more than a suicide mission.

Prime Minister Thaksin Shinawatra has blamed the violence on local gangs involved in smuggling and drug trafficking.

But there is an increasing fear that Islamic separatists were behind the attacks - helped by international militant organisations.

Brian Dougherty, from the Bangkok-based risk consultancy Hill and Associates, said that while those who took part could well have been members of criminal gangs, the more important question is why they did it.

The statistics show the inequality of the struggle - more than 100 of the machete-wielding attackers died, compared with just five members of the heavily-armed security forces.

"The organisers, at least, knew full well that many of them would be killed," Mr Dougherty said.

"This represents an ideological shift, and a major step-up in the problems of southern Thailand."

Separatist hopes

The alienation felt by Thailand's Muslim community - which is largely concentrated in the southern provinces - has been the source of a decades-old separatist struggle.

If you said a religious movement was to blame, you would immediately ignite Muslim sentiments Sajjan Gohel, Asia-Pacific Foundation

The violence abated in the late 1980s, but a raid on an army depot in Narathiwat province in January ignited fears of a return.

Few, though, would have predicted the scale of Wednesday's violence.

"The number of people killed in yesterday's clashes is about the same as usually die in a year (from separatist violence)," said Sajjan Gohel, a security analyst from the Asia-Pacific Foundation.

Analysts point to a number of local Muslim groups that could have been behind Wednesday's attacks - including Pulo (the Pattani United Liberation Organisation), BRN ( the Barisan Revolusi Nasional) and GMIP ( Gerakan Mujahadeen Islam Pattani).

These groups have long been campaigning for a separate Muslim state - similar to the Islamic Sultanate of Pattani, that became part of Thailand about a hundred years ago.

More than 100 of the militants were killed, 30 of them in a mosque raid

In the past, these groups have been linked with larger Islamic organisations such as Jemaah Islamiah (JI) - blamed for terrorist attacks across South East Asia - and GAM, the rebel movement in the troubled Indonesian province of Aceh.

In the wake of the recent attacks, there are fears these connections may still be alive and well.

"I don't believe the violence is just due to small gangs operating in isolation," said Sajjan Gohel.

He points to the arrest of Hambali, who is thought to be the operations chief for JI and dubbed the Osama Bin Laden of South East Asia.

Hambali was detained in Thailand in 2003, and is believed to have been given shelter there for a time - clearly indicating he had contacts in the region.

There is also evidence that many members of Thailand's Islamic groups, especially Pulo, were given training by militant organisations in Afghanistan and Pakistan.

But while JI, or an organisation like it, may have influenced Wednesday's attacks, analysts believe local groups are much more likely to have been in overall control.

"Muslims of southern Thailand are a very proud people - with their own culture and language," said Panitan Wattanayagorn, a political science professor at Bangkok's Chulalongkorn University.

"They are anxious to protect their own identity," he said.

While JI shares the same Muslim ideals as local groups, its aim is the creation of a pan-Asian Islamic super-state, rather than the relatively small secessionist struggle waged by organisations such as Pulo.

And whether international militant groups were implicated in Wednesday's violence or not, they could still exploit the growth in Islamic radicalism which appears to exist in Thailand's southern provinces.

"The incident has attracted attention to this area in the future as a fertile recruiting ground," said Mr Gohel.

Government line

Despite the evidence to the contrary, Prime Minister Thaksin so far insists that Wednesday's violence was perpetrated by teenagers hired by criminal gangs.

Security officers are now patrolling the troubled southern provinces

According to Panitan Wattanayagorn, the Thai government has good reason not to admit to the involvement of an Islamic group.

"If you said a religious movement was to blame, you would immediately ignite Muslim sentiments," he said.

Sajjan Gohel also cites the reluctance of governments in general to admit to problems of militancy within their borders.

"They seem to think it would create internal insecurity," he said. "But they need to understand it's a global issue, and it's not necessarily the country's fault."

"Terrorism is like the Sars virus," he said. "It spreads wherever it wants."