TWO senior executives at Binance have been detained in Nigeria as the country cracks down on cryptocurrency exchanges, the Financial Times reported, citing people familiar with the matter. The executives flew to Nigeria following the country's decision to ban several cryptocurrency trading websites last week but they were detained by the office of the country's national security adviser and their passports seized, the report said. Binance did not immediately respond to a Reuters request for comment. The crackdown follows a period after several cryptocurrency websites emerged as platforms of choice for trading the Nigerian currency, which has suffered chronic dollar shortages. The…