Binance.US said the move was the result of a periodic review and that factors it regularly considers can include trading volume and liquidity, changes in a token's risk profile or evidence of fraud or unethical conduct, among others.

The TRON token fell nearly 5% against the U.S. dollar after the announcement, which was posted on Twitter and the Binance.US website, while the much smaller Spell token fell more than 5%, based on data from CoinMarketCap.

The two tokens will be de-listed on April 18, Binance.US said. Withdrawals of both will remain open, but trading and deposits will close.

Justin Sun, founder of the TRON token, told Reuters in a text message that the impact would be "relatively small".

"Binance.US trading volume is less than $1 million per day. TRX's current trading volume is $400 million," said Sun, using the token's ticker symbol. Sun was accused of fraud by the U.S. Securities and Exchange Commission (SEC) last month.

Sun has previously said the SEC's "complaint lacks merit", and that the SEC's framework for regulating digital assets "is still in its infancy and is in need of further development".

Reuters was not immediately able to contact Spell representatives.

(Reporting by Kanjyik Ghosh in Bangalore and Rae Wee and Chen Lin in Singapore; Editing by Christopher Cushing)