PARIS —  Fire broke out in a Paris Metro (search) train Saturday, spreading to a second train and injuring 12 people before it was extinguished, officials said.

Paris subway officials said the fire may have been caused by a short circuit in one of the cars and was put out by 6:30 p.m., about two hours after it started. Five of the injured were on the train where the fire started, near the Simplon (search) station in northern Paris.

Another seven passengers were injured when their train, traveling in the opposite direction, caught fire as it sped past.

Transport officials said several stations would be closed until at least Sunday on the line connecting Porte d'Orleans in the south of Paris to the northern Porte de Clignancourt (search) station, a tourist stop known for its weekend flea market.

The fire came amid heightened security in the Paris subway following the bomb attacks on London's transport system last month.