Brazilian federal prosecutors have asked a judge to file corruption charges against former president Luiz Inacio Lula da Silva.

The prosecutors had been investigating whether Lula and his wife failed to declare ownership of a luxury penthouse in the seaside resort of Guaruja.

He has denied owning the flat and says the case is politically motivated.

The flat was built by a construction company implicated in a corruption scandal at state oil company Petrobras.

A former union leader, Lula served as president from 2003 to 2010.

A judge is due to rule in the next few days whether to formally charge him.