On Tuesday, the world’s largest cryptocurrency trading platform by volume, Binance, announced that withdrawals of the stable coin USDC were being paused. The announcement came after the platform had seen a surge of outflows following the collapse of rival cryptocurrency exchange FTX, according to media reports.

Investor concerns had been growing over Binance’s stability following the collapse of FTX and the ensuing bankruptcy proceedings and criminal investigation in the United States over the misuse of  customer funds.

In a statement, Binance said the pausing of withdrawals of USDC was due to a “token swap,” or the exchanging of one cryptocurrency for another.

The USDC cryptocurrency is classified as a stablecoin because its value is pegged, one to one with the US dollar. Exchanges use stablecoins to facilitate the trade of cryptocurrencies, without needing to move them back and forth into and out of actual dollars.

Binance’s chief executive Changpeng Zhao tweeted on Tuesday, “On USDC, we have seen an increase in withdrawals.”

Zhao noted that Binance need to swap USDC with two other crypto tokens, Paxos Standard and Binance USD. That would require using traditional dollars at a bank in New York. He went on, “The banks are not open for another few hours. We expect the situation will be restored when the banks open.”

He also noted, users could still withdraw other stablecoins on the platform, including Tether and BUSD.