LAFAYETTE (CBS SF) – A CHP patrol vehicle that caught on fire while traveling westbound on Highway 24 in the East Bay late Tuesday morning shut down lanes as the flames and heat set off ammunition inside, according to authorities.

The fire involved an off-duty CHP SUV that was traveling westbound on freeway near the St. Stephens exit at about 10:20 a.m. when it started smoking

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The officer driving pulled the vehicle over and exited it before it burst into flames. The heat from the fire caused some ammunition inside to explode, but there were no injuries reported.

The right lanes were closed as CHP and fire units responded. For a brief period of time, officers detoured traffic off the freeway at St. Stephens as firefighter put out the fire.

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Once the fire was put out, the freeway reopened just before 10:40 a.m., though the right lanes remained closed during clean-up as crews cleared the vehicle from the scene.

The SUV was loaded onto a flatbed tow truck shortly after 11 a.m.

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There was no word yet on what caused the fire.