15 held in Thailand not linked to tourist bombs: Police

Some of the 15 detainees accused of setting up an illegal political party to overthrow the regime are put on display at the Crime Suppression Division in Bangkok on August 19, 2016 AFP/Lillian Suwanrumpha

The junta said Thursday the detainees had been held during their investigation into the bombing spree, which hit tourist towns in the south, killing four and wounding dozens, including Europeans.

But on Friday police said the group - many of whom are elderly - had in fact set up an illegal political party to overthrow the regime.

The bombs attacks were highly unusual in a country where foreigners and tourist towns are rarely caught up in the country's frequent bouts of political violence.

Investigators have been under pressure to make quick arrests.

The group appeared at a Bangkok police station on Friday escorted by soldiers - the first time they have been seen in public - to hear the charges against them.

Two are women and many of the men are in their 60s and 70s.

Thai media have run multiple reports quoting anonymous investigators as saying the group helped coordinate the recent attacks.

But Major General Chayaphol Chatchaidej, a senior official at the Office of Police Strategy who was at the police station to receive the suspects, told reporters they were not involved.

"There is no evidence linking them to the bomb attacks in the seven southern provinces based on our investigation, although some of them are involved with lese majeste (royal defamation) and arms trafficking," he said.

Instead he described them as a splinter faction of the anti-junta Red Shirt movement loyal to ousted Thai premier Thaksin Shinawatra, who was toppled by the military in 2006.

He said the network called itself the Revolutionary Front of Democracy party - a previously unheard of group.

A police statement handed to reporters listing the suspects' names and ages said the group aimed to "accumulate arms... and overthrow the government" but made no reference to last week's bomb attacks.

The statement said they currently face one charge of breaching the junta's ban on political gatherings and another of belonging to an unlawful secret society.

That means no arrests or charges have yet been announced for people directly responsible for the blasts.

Thai police and military have a history of rivalry but since the 2014 coup the military have spearheaded national security investigations.

Previous bomb probes - including an attack on a Bangkok shrine last year that killed 20 - have been marred by confusion and conflicting statements.

Police and the military have ruled out international terrorism for last week's attacks, saying the perpetrators were "local saboteurs".

A number of analysts say the most likely culprits are ethnic Muslim militants who have fought a lengthy but local insurgency in Thailand's three southernmost provinces.

The attacks bore many hallmarks of the southern insurgents - who never claim their operations - including coordinated multiple strikes and the type of devices used.

But the junta leadership has been adamant that the deep south conflict has not spread north. Instead their focus has centred on domestic political groups who are opposed to their rule.

The Red Shirts have denied any involvement and accused the junta of using the bombs as an excuse to further crack down on opponents.