US Attorney General Eric Holder warned Monday that no financial institution should consider itself "above the law," amid investigations into alleged tax evasion and money laundering by European banks.
“There is no such thing as 'too big to jail'," Holder said. Separately, a senior US official told AFP on condition of anonymity that probes of BNP Paribas and Credit Suisse are expected to lead to charges.
Holder did not cite the French and Swiss banking giants by name, but his weekly audio message warned that the US Justice Department would "follow the facts wherever they lead."
US law enforcement and regulatory authorities have been criticized since the financial crisis of 2008 for not bringing criminal charges against some institutions and individuals accused of fraud.
But Holder, whose department oversees the FBI and its financial crimes task force, denied that the United States was unwilling to prosecute the pillars of the international banking system.
He rejected "the theory that certain financial institutions ... should be considered immune from prosecution due to their sheer size and their influence on the economy."
And he insisted: "To be clear: no individual or company, no matter how large or how profitable, is above the law."
BNP Paribas is under investigation over allegations of money-laundering and of breaching US financial sanctions against certain third parties, the senior US official told AFP.
Credit Suisse faces a separate inquiry into claims that it helped US citizens evade taxation by sheltering their funds abroad, he added.
"While I will not specify any particular targets, I will say this: I am personally monitoring the status of these ongoing investigations, I am resolved to see them through," Holder said.
"And in doing so, I intend to reaffirm the principle that no individual or entity that does harm to our economy is ever above the law.”
The US official said formal charges could be brought "in the near future."
Press reports have suggested that Credit Suisse could find itself facing a greater fine than the $780 million that its fellow Swiss rival UBS paid to US authorities in 2009.
And, according to the Wall Street Journal, BNP Paribas is in talks with US authorities to reach an out of court settlement.