The central probe agency said the assets were in the name of "Modi and his group company M/s Firestar Diamond FZE and they bear a market value of USD 7.79 million, which is equivalent to Rs 56.8 crore".
The ED has issued a provisional order for attachment of these assets under the Prevention of Money Laundering Act (PMLA).
Last month, the agency had attached assets worth Rs 637 crore of Modi and his family members, including two apartments at New York's iconic Central Park.
Sources in the agency said the ED would soon get multiple letters rogatory (judicial requests) issued by a Mumbai court for the legal formalisation of the attachment of these assets in coordination with its counterpart in Dubai.
Once the LRs were issued, India could freeze the foreign assets of an accused as part of a global legal cooperation in criminal matters, they added.
Modi has been absconding since the alleged bank fraud, by far the biggest in the country, came to light early this year and an Interpol arrest warrant was recently notified against him even as India is working to get him extradited from the UK, where he was last reported to have been based.
The agency has attached assets worth over Rs 700 crore of Modi and his family in the country till now. It has also filed a chargesheet against the fugitive diamond jeweller, alleging that he laundered and diverted over Rs 6,400 crore of bank funds to dummy companies abroad, which were under his and his family's control.
Modi, his uncle Mehul Choksi and others are being probed under various criminal laws, following a complaint by the PNB that they cheated the nationalised bank to the tune of over Rs 13,000 crore with the purported involvement of some of its employees.