Algiers - A 16-year-old German girl missing since early December has been picked up by Algerian police.

The Algerian news site Ennahar Online and other local media reported on Monday that the girl, from the northern German port city of Hamburg, had travelled alone to Algeria to be with her 19-year-old boyfriend.

The two were both taken into police custody after being found in the apartment of the young man south-west of the capital Algiers.

According to the Algerian reports, the young man was expelled from Germany last October after his application for asylum had been rejected.

The reports said he and the girl met in 2015 and that she had converted to Islam. Pictures in the media showed her in Germany wearing a black headscarf.

By earlier German media accounts, the Hamburg girl had disappeared in early December. Last week, police launched a public search for her. The last known contact for her was with her mother via the internet.