Binance, the world’s largest cryptocurrency exchange, has restricted the personal accounts of 281 Nigerian users, citing a need to comply with international money laundering laws, its CEO said.

Changpeng Zhao said in a letter to Nigerian customers dated Jan. 29 that the decision to restrict some personal accounts was to ensure user safety while more than a third of the affected accounts were restricted at the request of international law enforcement.

“Currently, we have resolved 79 cases and continue to work through others. All non-law enforcement-related cases will be resolved within two weeks,” Changpeng Zhao said.

Despite a central bank ban, Nigerians have continued to turn to crypto for business, to protect their savings as the naira currency loses value, and to send payments abroad because it is often hard to obtain U.S. dollars locally.