The Enforcement Directorate (ED) on Saturday said it has attached diamond trader Nirav Modi's 21 immovable properties worth Rs 523.72 crore in connection with an ongoing probe into Rs 11,300-crore Punjab National Bank (PNB) fraud case.

The assets include a farm house in Alibaug (Rs 42.70 crore) near Mumbai seashore, a solar power plant spread over 53 acre of land in Ahmednagar in Maharashtra (Rs 70 crore) and another 135 acre land in Ahmednagar (Rs 2.20 crore), along with other residential and office properties worth Rs 408.82 crore in Mumbai and Pune.

On Friday, the ED said it had frozen Nirav Modi's bank account and shares worth Rs 43 crore. The ED had earlier seized bank deposits, shares and luxury cars worth over Rs 100 crore belonging to the businessman and his group.

The agency has also frozen Mutual funds and shares worth Rs 7.80 crore of Nirav Modi and Rs 86.72 crore belonging to his uncle Mehul Chokshi of the Gitanjali Group.

The agency's action comes in the wake of its ongoing probe -- along with the Central Bureau of Investigation (CBI) -- against the two and many others including directors of their companies and bank officials into the alleged bank fraud.

Both central agencies had conducted multiple raids at the residential and office premises and showrooms of the accused traders ever since the CBI filed two FIRs on February 14-15 against Nirav Modi and the Gitanjali Group of companies.

The CBI filed the first FIR against Diamond R Us, Solar Exports and Stellar Diamond, whose partners have been named as Nirav Modi, his brother Nishal, uncle Mehul Choksi and wife Ami -- who left the country in early January. The fraud by Nirav Modi group is said to be around Rs 6,400 crore.

The second was FIR filed on February 15 for Rs 4,886.72 crore fraud against the Gitanjali group headed by Choksi.

Letters of Undertaking and Foreign Letters of Credit were used to raise and rollover the amount for several years before the fraud came to light.