The accident happened when a 10-wheel truck rammed into a car and a pickup truck as they waited for a green light, said Pol Lt Rungroj Toro, an investigator at the Photharam police station.
The pickup then crashed into another sedan and three other trucks in the middle of the intersection in tambon Nong Pho in Photharam district.
Several vehicles caught fire as one of them had a liquefied petroleum gas (LPG) tank. Pol Lt Rungroj said the 10-wheeler's brakes had failed, causing the crash that killed an elderly woman and a girl about six years old. The injured were rushed to Photharam Hospital.
The accident also caused traffic to back up for about 10 kilometres.