Thailand bomb attack
A man looks at the site of an explosion on 12 August, 2016 in Hua Hin Dario Pignatelli/ Getty Images

As the dust settles on the bomb blasts that struck Hua Hin and Phuket on Friday attention has turned to the motivation of the bombers and, most notably, to whether the attacks that killed three and injured dozens are linked to the violent insurgency being fought in the south of the country between Muslim separatists and the Thai state.

The Thai authorities have not revealed who they believe were behind the attacks, which targeted popular tourist sites almost exactly a year after 20 were killed at the Erawan shrine in Bangkok in 2015, but ruled out a terrorist motive. But critics note that this denial may be an effort to downplay the impact on tourism, Thailand's lifeline.

"When Thai police say they have ruled out terrorism, they have done nothing of the sort. The authorities in Thailand [...] are desperate to minimise the damage to tourism, and will say anything they think will achieve this," said Andrew MacGregor Marshall, author of A Kingdom in Crisis: Thailand's Struggle for Democracy in the Twenty-First Century. "In fact, police have no idea at this stage who was behind the bombings."

The nightmare scenario for the Thai government, MacGregor Marshall said, was that Muslim separatists in the south of the country had transposed what has been a localised conflict with the Thai state for over a decade to high-profile attacks on tourist centres.

"The southern border area has been restive and lawless for decades, but some analysts have long predicted that the conflict could escalate, with international jihadists joining the fight and attacks being staged beyond the deep south. It is possible that these attacks herald the beginning of a new phase in the southern insurgency," he said.

Thailand suffered a renewed outbreak of hostilities in the southern provinces of Yala and Pattani in February 2016, which saw arson attacks, drive-by shootings and roadside bombs targeting the Thai military. Over 12 years the conflict between the army and a number of Muslim separatist groups has cost between 5,000 and 6,500 lives.

Whoever is behind this, it is a turning point.

In July, militants shot dead two Thai soldiers and burned their bodies, the Thai authorities claimed, three days after one soldier was killed and another three injured in a roadside bomb. The population of Yala, Pattani and a third Muslim-majority province, Narathiwat, are mostly ethnic Malays who complain of years of poverty and neglect since the provinces were incorporated into the Thai state a century ago.

Back in 2015, Paul Chambers, director of research at the Institute of Southeast Asian Affairs in Chiang Mai, told German broadcaster DW that the type and magnitude of rebel attacks had been increasing – with the use of road-side bombs "an alarming trend". He said that the change in tactics indicated a desperation on the part of insurgents and a willingness to dare to be more destructive and radical.

Speaking to IBTimesUK on Friday, Chambers said that Muslim insurgents in the south were the most likely culprits given that they had both the access to explosives and weapons and the wherewithal to carry out such an orchestrated and multi-pronged attack. But there were other culprits too: anti-junta forces allied to exiled former Prime Minister Thaksin Shinawatra.

Thitinan Pongsudhirak, director of the Institute of Security and International Studies at Chulalongkorn University in Bangkok, said that Muslim separatists in the south had, with very few exceptions, concentrated their attacks to southern provinces where they can carry out violence at will. If they had wanted to send a message to the Thai government, he said, they would have likely targeted major cities like Bangkok or Chang-Mai.

He ruled out the involvement of international jihadi groups: "External terrorism from the likes of Islamic State and elsewhere also has not been able to make inroads into Thailand's Malay-Muslim insurgency, and terrorism is thus an unlikely cause this time," he said.

Pongsudhirak sees the likely motive behind the attacks as political, coming so soon after Thailand's military junta – which seized power in 2014 – won a referendum to impose a military-inspired constitution that gives the regime far greater power over the country's 250-strong legislature. The anti-junta forces that lost the referendum, he suggests, could be showing defiance after 61% of the country voted in favour.

"The tourist resorts that have been targeted, including globally recognisable destinations like Phuket and Hua Hin, are located in the southern provinces that voted overwhelmingly for the pro-military charter. Tourism also provides a lifeblood for the Thai economy. Targeting these destinations discredit the military's vaunted ability to maintain law and order and dampen economic prospects under the junta rule," he said.

The date of the bombings, on Queen Sirikit's 84th birthday, was also significant. The dominant faction of Thailand's military regime is linked to the Queen's Guard while the other rival branch is the Kings Guard, loyal to ageing 88-year-old King Bhumibol. The Queen is no longer involved in politics – she suffered a stroke in 2012 – but her clique has always opposed the power base of her husband and the couple have been estranged for decades.

Equally Hua Hin, which was targeted by four of the 11 bombs, is the political stronghold of notorious royalist Suthep Thaugsuban, a close ally of the junta, said MacGregor Marshall: "The symbolism of the attacks may suggest they are a result of political or economic conflict and aimed at the dominant military and mafia cliques."

But whoever carried out the attacks, their significance should not be underplayed. Not since the Communist insurgency of the 1960s and 1970s has Thailand seen such a well-planned and coordinated attack against multiple locations: "Whoever is behind this, it is a turning point," Chambers said. "Thailand has never experienced bomb orchestration of this magnitude."