Researchers in Italy say they may have found traces of a Leonardo Da Vinci work hidden under a Florentine fresco.

Tiny probes, sent through drilled holes in Giorgio Vasari's The Battle of Marciano in the Palazzo Vecchio, found black pigment also used in the Mona Lisa, project workers claimed.

"These data are very encouraging," said the project's leader Maurizio Seracini.

But historians at a press conference in Florence stressed their research was "not conclusive"....