Police say a pack of wild pigs popped under a fence onto a stretch of the German autobahn, shutting the highway down for hours.

Police in Lower Saxony said Thursday that at about 2:30 a.m. the pigs apparently dug under a fence designed to keep them and other wildlife off the high-speed road.

Firefighters closed down a stretch of the highway but were unable to locate pigs, even with the help of thermal-imaging cameras.

Germany's DAPD news agency says the autobahn was reopened after three hours when it was believed that the pigs had left on their own accord.