BEIRUT (AFP) - Two Germans kidnapped in eastern Lebanon were freed on Saturday, hours after their abduction, but police immediately arrested them on drug trafficking charges, the official National News Agency reported.

"The Germans abducted last night in the eastern Bekaa Valley were released today," NNA said. "After they were freed, a police unit from the Internal Security Force arrested the Germans on charges of drug trafficking, and a search for the abductors is under way."

The Germans were seized on Friday by unknown gunmen demanding a ransom for their release, in what a security official said appeared to be a criminal rather than a political act. The official told AFP late on Friday that the abduction was more likely "for financial reasons", adding that a Lebanese man called a friend of the Germans demanding ransom of 6,000 euros (S$10,000).

The Bekaa Valley, which borders war-hit Syria, is a lawless but fertile region where drug cultivation and trafficking has flourished for years. During the 1975-1990 civil war, the drug trade grew into a multi-billion dollar industry in Lebanon.

The Lebanese authorities have struggled to eradicate the drug trade and carry out repeated army and police patrols in the region to impose the law, but farmers who mostly cultivate hashish constantly defy them.

Friday's kidnapping was the first of its kind since 2011, when a group of seven Estonian cyclists were abducted and held for four months.