Thailand's police chief Tuesday linked the Bangkok bomb to China's Uighurs for the first time, as the lawyer for one of two detained foreign suspects confirmed his client is from the Muslim minority.

For weeks Thai police have skirted around mentioning the word Uighur or suggesting their possible involvement in the attack, despite arrests and warrants that increasingly pointed in that direction.

The August 17 bombing killed 20 people, the majority of them ethnic Chinese tourists, raising the possibility of a link to militants or supporters of the Uighurs, an ethnic group who say they face heavy persecution in China.

A month earlier Thailand had forcibly deported more than 100 Uighur refugees to China, sparking international condemnation as well as violent protests in Turkey, where nationalist hardliners see the minority as part of a global Turkic-speaking family.

Police blame a gang of people smugglers for the attack, motivated by revenge for a crackdown on their lucrative trade through Thailand, a motive which has been widely dismissed by security experts.

"The cause was the human trafficking networks -- networks transferring Uighurs from one country to another. Thai authorities destroyed or obstructed their human trafficking businesses," Somyot Poompanmoung told reporters on Tuesday, explaining the apparent motive for the attack.

It was the first time Thai police have formally referenced the Uighurs in relation to the case, after issuing a retraction of a mention of the group over the weekend.

Thailand's junta chief Prayut Chan-O-Cha later questioned why Uighurs would carry out an attack yet not claim it.

"But I don't rule out this motive yet," he told reporters.

Mostly Muslim Uighurs have long accused Beijing of religious and cultural repression in China's far western Xinjiang region, with hundreds of refugees believed to have fled in recent years, often heading to Turkey via Southeast Asia.

- Wary of upsetting China -

Analysts say Thailand is keen to avoid naming Uighurs for economic and diplomatic reasons.

Chinese visitors are a lynchpin of the tourist industry, and Beijing remains one of the increasingly isolated Thai junta's few international allies.

But arrest warrants, passports and travel itineraries of the main suspects all point towards the involvement of militants from the ethnic group or their supporters.

Nearly a month on, Thailand has two foreigners in custody and a dozen arrest warrants issued.

One of the two men in custody, Yusufu Mieraili, was seized with a Chinese passport that gave a Xinjiang birthplace. Police say they believe his passport is real.

The other suspect, named by Thai police as Adem Karadag, was allegedly discovered in a flat on the outskirts of Bangkok in possession of bomb making equipment and dozens of fake Turkish passports.

Speaking to the media on Tuesday, his lawyer said his client -- whose real name is Bilal Mohammed -- admits entering Thailand illegally but denies any knowledge of the the bomb plot.

"He has denied that any of the bomb making materials belong to him," lawyer Chuchart Kanphai told AFP. "Most of stuff in that room was there before he arrived."

Chuchart said Mohammed was born in Xinjiang's capital, Urumqi, but moved to Turkey in 2004 where he received Turkish nationality and found work as a truck driver with his brother.

He entered Thailand on August 21, four days after the bomb blast, with the aim of finding work in Malaysia, the lawyer said.

A broker helped him get into Thailand with a fake passport via Vietnam and Laos, and arranged for him to stay at the flat that police later raided and allegedly discovered explosives.

The broker "promised him work in Malaysia, such as being a driver or a painter or a cleaner", Chuchart said.

Almost all the other suspects identified by police have Turkish sounding names or links.

On Monday police said another suspect, Chinese national Abudusataer Abudureheman -- who investigators say was in contact with cell members before the blast -- flew out of Thailand on August 30 to Bangladesh before heading on to Delhi, Abu Dhabi and eventually Turkey.

On Tuesday the Turkish embassy in Bangkok said it had yet to be contacted by Thai police on that development.