About 15 gunmen ambushed two vans carrying millions in jewels Wednesday on a French highway, forcing out their drivers in the middle of the night and speeding off into the Burgundy countryside, police said. It was the latest in a string of big jewel heists in France.

French gendarmes and other authorities were combing the forests and towns in the region southeast of Paris for the attackers. No one was injured in the attack on the A6 highway connecting Paris and Lyon, and the drivers of the two vans were left at the scene unharmed, a police official said.

The perpetrators escaped in four cars and the two vans, which police later found burned and abandoned near the site of the attack, the official said. Forensic investigators in white suits examined the area around the charred vans amid vineyards in the town of Quenne.

The jewels remain missing and it's unclear where the attackers were heading. After hours of searches failed to locate them, another police official said authorities were concentrating efforts on the investigation into the attack, which was handed to the French police agency overseeing organized crime.

The officials spoke on condition of anonymity because they were not authorized to be publicly named.

No possible suspects have been named in Wednesday's theft, although the case was reminiscent of heists by the Pink Panther gang of jewel thieves. The Pink Panther network has been credited with a series of thefts that Interpol says have netted more than 330 million euros since 1999.

France has seen repeated jewelry thefts. In November, two gunmen robbed a Cartier jewelry boutique in a tony, tourist-filled Paris neighborhood, fled a police chase across the Seine River, took a hostage — and then surrendered.

Last month, eight people were convicted in connection with a spectacular 2008 jewel theft at a Harry Winston boutique in Paris, when three cross-dressing gunmen stole about $92 million in goods.

In 2013, southeast France was hit with a spate of jewelry thefts, including two in Cannes during the city's famed film festival. In one, a gunman walked into a jewel show at the Carlton International Hotel, stole $136 million in loot, and disappeared down a side street in one of the most lucrative jewelry heists ever.