Five employees of China's biggest bank have been arrested in Spain on suspicion of laundering money across Europe.
Police made the arrests Wednesday after raiding the offices of the Industrial and Commercial Bank of China in Madrid. One of those detained was the director of the bank in Spain, a source with knowledge of the investigation told CNN.
European law enforcement officials said Beijing-based ICBC (IDCBY) was suspected of laundering money on behalf of a Chinese criminal enterprise that allegedly imported a huge amount of goods without proper customs declarations, in order to avoid Spanish taxes.
The bank also allegedly provided services to other Chinese and Spanish criminal syndicates "to introduce into the financial system funds earned through the crimes of smuggling, tax and excise fraud and labor exploitation, allowing the transfer of the funds to China in a way that appeared legal," European law enforcement agency Europol said in a statement.
Related: Chinese snap up fine art for use in laundering schemes
The investigation into the suspected laundering of at least 44 million euros had identified other links leading to France, Germany and Lithuania, Europol said. It gave no further detail.
State-owned ICBC, which launched its Spanish operations in 2011, is the world's biggest bank with about $3 trillion in total assets.
Related: China busts $64 billion underground banking ring
The Chinese embassy in Madrid said in a statement that Chinese institutions operating in Spain abide by and comply with local and Chinese laws, adding that it was following developments closely.
Attempts to reach ICBC by phone and e-mail for comment were unsuccessful.
-- Correction: An earlier version of this story incorrectly stated ICBC's total assets as $250 billion. The correct figure is $3 trillion.
-- With reporting from Laura Perez-Maestro in London