A bomb exploded in front of a busy market in the southern Thai province of Songkhla, killing four people and wounding about 25, officials say. The bombing came a day after at least 13 people were hurt when six bombs exploded Sunday evening in the city of Hat Yai, southern Thailand's tourist and commercial hub in the same province. Monday's bomb in Sabayoi district, which exploded shortly after 4 p.m., had been hidden in a motorcycle parked in front of the market next to a railway station, police was quoted as saying by the Associated Press.