The 24-year-old forward spent the second half of last season on loan at Fiorentina, where he scored twice in 15 Serie A outings.
Now La Viola want to land him on a permanent deal from Barcelona, as do their domestic rivals AC Milan.
But, according to reports, Southampton remain in pole position to sign the Spaniard this summer despite the interest from Italy.
However Spanish newspaper El Desmarque has revealed that both Italian clubs have now lodged formal bids for Tello and are currently awaiting a response from Barcelona.
It has also been suggested that Southampton are yet to firm up their interest with an offer for the £10m-rated ace – which could open the door for either Fiorentina or AC Milan to win the race.