Police have detained two senior executives from Guangdong Development Bank, a mid-sized Chinese lender in which Citigroup owns 20 per cent, on suspicion of economic crimes.

Wang Xin, GDB's vice-president, and another unnamed department head, were detained last week in connection with unspecified economic crimes, a source with direct knowledge of the matter told the Financial Times.

Li Ruohong, GDB's chairman, stepped down for health reasons last week after a long dispute over the terms of his departure but his resignation had nothing to do with the detention of the two executives, according to people familiar with the matter. The detentions, which were also reported in Chinese media, are just the latest in a string of scandals to hit the Chinese financial sector, where bribery and corruption are endemic and rules are constantly changing and often unclear.