Thai police chief Somyot Poompanmuang has said that at least 10 people, including both Thai and foreigner nationals, were involved in the deadly Bangkok blast, as police said they were seeking two new suspects in the case.

On Monday, police probing the country's deadliest bombing raided a second location in the capital city's outskirts and widened their search for more suspects a day after a foreigner was arrested and stacks of fake passports and bomb-making materials were found at a Bangkok apartment block.

The police operations are in connection with the bombing at the Erawan shrine in Bangkok's bustling downtown district on August 17, which killed 20, mainly tourists.

"The first one is a woman, Wanna Suansan, aged 26," national police spokesman Prawut Thavornsiri said in a televised broadcast on Monday that named a suspect in the case for the first time and showed a photograph of a young woman in a hijab.

"There is also another person living in the room, he is a man, nationality unknown," he added.

Police have found uncovered fertiliser, digital watches and an explosives detonator in a raid in Bangkok's Min Buri district, Thavornsiri said.

Police arrested an unidentified foreign man in a high-profile raid on Saturday at a building in nearby Nong Chok district of the capital, where they discovered explosives and piles of fake passports.

Police had been searching for a prime suspect, described as a foreign man, who was wearing a yellow T-shirt and was captured on security cameras leaving a bag at the shrine moments before the blast.

Investigators have said the attack was clearly aimed at damaging the tourism industry but insist that Chinese tourists - who visit Thailand in larger numbers than any other nationality - were not singled out as a target.

Last week Thai police said they were not ready to exclude any possibility about who was behind the attack.

Source: Agencies