During a televised statement, police broadcast a photograph of the woman`s Thai identification card showing a young woman in a black headscarf and a sketch of the man whose nationality was unknown.

The development came after police arrested a man from an apartment in Bangkok`s outskirts on Saturday and seized bomb-making equipment that included detonators, ball bearings and a metal pipe believed to be a bomb casing.

More bomb-making materials were discovered in a second apartment during a raid Sunday in a nearby neighbourhood, national police spokesman Prawuth Thavornsiri said Monday. He said the second apartment, in a neighbourhood known as Min Buri, was rented by the Thai woman identified as Wanna Suansun and 26 years old.

Prawuth described what police found as "important bomb-making materials such as gunpowder, urea-based fertilizer which can be used as explosive powder when mixed with other substances, a remote-controlled car with its controller which can be used as a detonator, nuts and bolts, small light bulbs and digital watches," among other things.

The man, whose face is shown in a police sketch with short brown hair and a light beard and moustache, is believed to have lived in the apartment, said Prawuth, adding that his nationality was not known.

Arrest warrants were issued for both the woman and man on charges of possessing unauthorized explosives, Prawuth said.

Saturday`s arrest marked the first possible breakthrough in the investigation into the Aug. 17 blast at the Erawan Shrine, which killed 20 people, more than half of whom were foreigners, and injured more than 120 others.

Much remains unknown about the suspect, including his nationality, his motive, his relationship to the alleged bombing network or if he was plotting an attack, Prawuth said, adding that another attack was "possible" because police found 10 detonators.

"We still have to work out the details," he said. "But we are very certain he`s part of the network" that carried out the bombing.

On Sunday, Prawuth said police were working with "a number of embassies" and interpreters to try to establish the man`s nationality, adding that he did not speak Thai but spoke some English.

Turkish connection speculation

Authorities have dodged questions about whether the suspect is believed to be Turkish, saying that he was travelling on a fake passport. Images circulated online after his arrest of a fake Turkish passport with the apparent suspect`s picture.

The Turkish Embassy in Bangkok could not immediately be reached for comment. A Turkish government spokesman contacted over the weekend in Istanbul said he had no information on the suspect or any possible Turkish link to the attack.

The blast at the Erawan Shrine was unprecedented in the Thai capital, where smaller bombs have been employed in domestic political violence over the past decade, but not in an effort to cause large-scale casualties.

No one has claimed responsibility for the blast, sparking a variety of theories into who might be behind it.

Possible suspects include parties seeking to avenge Thailand`s forced repatriation of ethnic Uighurs to China. Uighurs are related to Turks, and Turkey is home to a large Uighur community.

Other theories included Muslim separatists from southern Thailand, opponents of Thailand`s military government and feuding factions within the security services.

Erawan Shrine was unprecedented in the Thai capital, where smaller bombs have been employed in domestic political violence over the past decade, but not in an effort to cause large-scale casualties.

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