A DeKalb County sheriff’s cruiser carrying live ammunition burst into flames Friday afternoon on I-285, causing some scary moments for one deputy and traffic woes for thousands of drivers.

All lanes of I-285 westbound near Chamblee-Tucker Road were blocked and traffic was tied up for about two hours as fire crews rushed to the burning cruiser about 3 p.m., said Alisa Jackson, DeKalb fire spokeswoman.

Complicating matters: ammunition inside the cruiser discharged under the fire’s heat, Jackson said.

The deputy, who was not identified Friday afternoon, was not injured, she said.

An investigation will be conducted to determine what caused the cruiser to catch fire, Jackson said.