Three people were injured, one of them seriously, when lightning struck a beach packed with holidaymakers on Italy's Adriatic coast on Saturday, news reports said.

The bolt of lightning hit the stretch of beach near Alba Adriatica, in the central Abruzzo region, just after midday, wrote the ANSA news agency, which said that the beach was crowded at the time despite cloudy skies and bursts of rain.

Photos posted on social media showed emergency workers crowded around what appeared to be a woman on a stretcher on the beach.

ANSA reported that three women were hit, with the most serious a local woman who suffered a heart attack and was reanimated on the beach. She was then taken by helicopter to a nearby hospital, where she remained in intensive care.

A second woman, who ANSA identified as Belgian, temporarily lost feeling in her legs and was also receiving treatment in hospital, along with a third woman who also experienced paralysis in one leg.

Local authorities could not be immediately reached by Agence France-Presse (AFP).

Earlier news reports had said that as many as seven people had been struck by the lightning bolt.

The civil protection department warned on Saturday of unstable weather conditions in central Italy, with scattered thunderstorms and "frequent electrical activity".