Four Swiss bank accounts of diamantaire Nirav Modi, who is the main accused in the $2-billion PNB fraud case, and his sister have been 'frozen' by authorities in Switzerland as part of a money laundering probe being conducted against them in India, official sources said.

They said the accounts have deposits totalling Rs 283.16 crore and they have been frozen on the request of the Enforcement Directorate (ED) after it informed Switzerland that the money kept in them are 'proceeds of crime' of a bank fraud perpetrated by the duo.

The ED, they said, made the request to the Swiss authorities sometime back and sent an official request under the criminal provisions of the Prevention of Money Laundering Act (PMLA).

Official sources said that while the accounts of Modi have deposits of $3,74,11,596, his sister Purvi Modi's account has has 27,38,136 Pounds.

This totals around Rs 283.16 crore, they said.

The central probe agency is expected to now make a move for the attachment of these accounts.

The ED, along with the CBI, is investigating Nirav Modi, his uncle Mehul Choksi and others for alleged money laundering and corruption to defraud the Brady House branch of the PNB in Mumbai to the tune of over Rs 13,000 crore.

The alleged scam was unearthed last year and Purvi Modi was also named as an accused by the ED in its chargesheet filed before a Mumbai court.