Thai police unsure if foreign bomb suspect has fled the country

An arrest warrant has been issued for the unnamed suspect, who was filmed on security footage placing a backpack at the shrine before the blast that tore through the popular tourist site, killing 20 people -- mostly foreigners.

The Monday evening attack has left the city on edge and dealt a major blow to the country's cash-cow tourism sector.

Police appear to be have drawn a blank in their probe, and with no claim of responsibility and analysts confounded over a motive for a strike that has no precedent in the kingdom, speculation has filled the void.

"We are doing our best," police spokesman Prawut Thavornsiri told AFP.

"We have received a lot of information from the public since releasing of the sketch... we are investigating those leads," he said.

But when asked if the prime suspect was still in the kingdom he said: "I don't know."

The arrest warrant, which followed the circulation of the sketch of the alleged bomber drawn from security camera footage, described him as a tall fair-skinned foreigner.

It accused him "of premeditated murder, attempted murder and bomb-making".

Police believe he was part of a "network" and that two other men also seen on CCTV at the Erawan shrine before the blast may have been his accomplices.

Prawut has given a more detailed description of the suspected ethnicity of the alleged bomber, using the Thai phrase "khaek khao" -- a word used to describe light-skinned Muslims from South Asia, Central Asia and the Middle East.

Those comments came during a nighttime patrol Wednesday of Soi Cowboy -- one of Bangkok's most famous red-light districts which is packed with foreigners -- which was designed to reassure visitors.

Motive mystery

The bomb struck during Monday's rush hour in a popular tourist area in the city's commercial heart, studded by upscale shopping malls and hotels.

It claimed the lives of at least 13 foreigners -- from Britain, China, Hong Kong, Indonesia, Malaysia and Singapore.

Another 67 people remained in hospital by late Wednesday, 12 of whom were in critical condition.

Prime Minister Prayut Chan-O-Cha has described the bombing as the "worst ever attack" on Thailand.

It remains unclear who has the capacity and desire to carry out the mass casualty attack on a Southeast Asian nation that has not been hit by terrorism on such a scale.

Left with just guesswork, Thai media outlets have cast suspicion on militants from China's Uighur minority, a group that faces cultural and religious repression in its homeland.

The Erawan shrine is enormously popular among ethnic Chinese visitors from across Asia.

Last month Thailand forcibly repatriated more than 100 Uighur refugees to China, stirring speculation that Monday's attack may have been an act of revenge.

But Uighur groups are not known to have ever carried out an attack outside China.

Islamic militant groups have targeted parts of Southeast Asia, including bombings on Indonesia's holiday island of Bali in 2002 that killed 202 people.