Spain's 12-month inflation rate fell to 3.1% in December, down from 3.2% in the period through November, preliminary data from the National Statistics Institute (INE) showed on Friday.

The 12-month inflation was below the 3.2% expected by analysts polled by Reuters.

Core inflation, which strips out volatile fresh food and energy prices, was 3.8% year-on-year, the INE data showed.

Spain's European Union-harmonised 12-month inflation was 3.3%, unchanged from November and below the 3.4% expected by analysts polled by Reuters. (Reporting by Matteo Allievi, editing by Inti Landauro)