Germany's centre-left Social Democrats have narrowly beaten the party of outgoing Chancellor Angela Merkel in federal elections, according to preliminary results.

SPD leader Olaf Scholz says he has a clear mandate to form a government, but his conservative rival, Armin Laschet, is determined to fight on.

The two parties have governed together for years but are unlikely to continue.

Instead the Greens and liberals are looking for a role in a new coalition.

The two parties attracted the most support from the under-30s, in an election dominated by climate change and by differing proposals on how to tackle it. The Greens made history with almost 15% of the vote, even though it was well short of their ambitions.

It was the tightest race in years, bringing an end to the post-war domination of the two big parties - Mr Scholz's SPD and his rival's conservative Christian Democratic Union (CDU). For the centre-left it was a significant improvement on the last election, but for the conservatives it was their worst ever performance.