Bancor, an Israeli startup that facilitates trading in digital tokens, said a criminal made off with a $13.5 million cache, mostly comprised of Ether.

Using emergency protocols, the company managed to freeze an additional $10 million of its own Bancor tokens, known as BNT, limiting damage from the theft on Monday, the firm said in statement on Twitter. The breach occurred in a wallet used for certain contracts, it said, noting investigators are still pinning down details of what happened.

“We are now working together with dozens of cryptocurrency exchanges to trace the stolen funds and make it more difficult for the thief to liquidate them,” it said.

BNT was down almost 14 percent Monday evening in New York, according to CoinMarketCap.com. A message posted on Bancor’s website said it’s undergoing maintenance and “will be back online soon.”

Tel Aviv-based Bancor raised about $153 million in an initial coin offering last year. Its network effectively functions as an exchange that will automatically price and trade any cryptocurrency that wants to list with it. In its first year, Bancor processed more than $1 billion in token conversions, the company has said. It also recently launched a community currency in Kenya.

Bloomberg News