BANGKOK (Reuters) - Thai police on Wednesday arrested three men suspected of planning bomb attacks at tourist suites in the capital, Bangkok, and nearby provinces, a top officer said.

The three hailed from Thailand's Muslim-majority south, where a decades-old insurgency has pitted separatist militants against government forces, said deputy national police chief Srivara Ransibrahmanakul.

But he ruled out any link between the suspected plotters and the insurgency.

"All three came from the southern provinces and were prepared to carry out an attack in Bangkok and surrounding areas but we believe they are not separatists," Srivara told reporters.

"They planned to target tourist sites," Srivara said.

The three hoped to attack six locations, Srivara said, but he did not give details nor elaborate on what their motive might have been. Police said in a statement the plots were "designed to create unrest".

Thailand is predominantly Buddhist but the provinces of Yala, Narathiwat and Pattani, the first two of which border Malaysia, are majority Muslim and insurgents there have been fighting for autonomy for decades.

Bombings are common in the three southernmost provinces, where the insurgency has killed more than 6,500 people since 2004.

The trouble has been largely confined to the three provinces but a wave of bombs in tourist towns outside the deep south in August killed four Thai people and wounded dozens, including foreigners.

No group claimed responsibility for those attacks and authorities gave mixed signals about whether they thought the perpetrators were linked to the southern insurgency.

Security analysts say the government is reluctant to blame the Muslim insurgents because that would signal violence was spilling out of the traditional conflict zone, and perhaps posed a risk to the important tourist industry.

In October, police said they had increased security at major landmarks, including airports, following reports of bomb plots.

In August 2015, a bomb at a major religious shrine in Bangkok killed 20 people, most of them tourists from east Asia.

Two ethnic Uighur Muslims from China are on trial in Thailand accused of that attack. Police say they believe the bombers were retaliating against a crackdown on people-smuggling.

Analysts and diplomats suspected the attack was linked to Uighur sympathizers angered by Thailand's deportation of more than 100 Uighurs to China the previous month.

(Reporting by Amy Sawitta Lefevre and Aukkarapon Niyomyat; Writing by Amy Sawitta Lefevre; Editing by Robert Birsel)