Binance CEO Changpeng Zhao has claimed that the exchange suffered a distributed denial of service (DDoS) attack earlier today. He blamed rival exchanges for the incident, citing a pattern of behavior leading up to the hack.

"Earlier today, our Chinese domains experienced targeted DDoS attacks, and users saw some lag and interruption of network access. Based on the attack pattern, it looks like work of our self-perceived competitors. No need to be concerned. Systems are fine. Funds are SAFU," he tweeted.

Zhao added that the exchange has hackers working for Binance in order to ensure the exchange stays online. "We of course do. We also have self-perceived “competitors” doing testing for us. Everyone is working on Binance," he said.

Binance follows a number of other exchanges who claim to have suffered DDoS attacks in recent months. Notably, Bitcoin derivatives exchange BitMEX blamed its outage on March 12—during the most volatile day for Bitcoin in seven years—on such an attack. Commentators argued that BitMEX going down made the crash even more pronounced, while BitMEX said the attack was designed for maximum impact.

In February, crypto exchanges OKEx and Bitfinex also suffered simultaneous DDoS attacks. At the time Bitfinex CTO Paolo Ardoino said, "We've seen a level of sophistication that means a deep preparation from the attacker. Good news: this family of attacks won't work again against Bitfinex."

But it appears someone has it out for crypto exchanges—and they haven't stopped yet.