Thai police released a sketch on Wednesday of the main suspect in a bomb blast in Bangkok that killed at least 20 people, more than half of them foreigners.

The sketch shows a fair-skinned man with thick, medium-length black hair, a wispy beard and black glasses. It was unclear whether the man was Thai or a foreigner.

On Tuesday, a day after the bombing at a religious shrine in Bangkok's busy Ratchaprasong commercial district, police released grainy closed-circuit television footage of a young man wearing a yellow T-shirt.

The man is shown in closed-circuit television footage dumping a backpack and walking away from the scene of the blast minutes before the explosion.

Police have said the man is a suspect, but that others could be behind the attack. They have not ruled out any group, including elements opposed to the military government, though they said it did not match the tactics of Muslim insurgents in the south or 'red shirt' supporters of the previous administration.

The sketch, say police, could help locate the yellow-shirted man. A 1 million baht ($28,000) reward has been offered.

(China Daily 08/20/2015 page12)