As the fallout continues from sweeping revelations of massive tax evasion allegedly orchestrated by HSBC’s Swiss subsidiary, Belgium this week signaled the possibility of hitting some of the private bank’s managers with arrest warrants.

According to reports by Deustche Welle and other media outlets, Belgian officials are frustrated by a lack of cooperation from HSBC, whose Swiss unit is facing charges in the country for fraud and money laundering totaling hundreds of millions of euros. Prosecutors said the company has fallen short in its pledge to cooperate.

Belgian investigating judge Michel Claise reportedly said on Monday he is considering whether to issue international arrest warrants for former and current directors of the HSBC Swiss unit, Deutsche Welle reported.

“The bank is not giving the required information voluntarily. The judge has said that if it’s so hard to get the information, he’s considering international arrest warrants for the present directors in Belgium as well as Switzerland,” a spokeswoman for the Belgian prosecutors told Reuters.

Belgium and other countries are facing pressure to step up investigations into London-based HSBC after blockbuster revelations this weekend by the International Consortium of Investigative Journalists (ICIJ) that the bank’s private Swiss unit helped hide millions for clients, including arms dealers and dictators’ associates. The “Swiss Leaks” investigation revolved around a cache of leaked documents detailing accounts of more than $100 billion in 2006 and 2007, showing illegal tax evasion that benefited celebrities, executives, and figures tied to arms dealing, blood diamonds, and bribery.

The bank acknowledged the problems in a written statement to ICIJ, the investigative team reported. “We acknowledge that the compliance culture and standards of due diligence in HSBC’s Swiss private bank, as well as the industry in general, were significantly lower than they are today,” HSBC’s statement said. The bank said it has “taken significant steps over the past several years to implement reforms and exit clients who did not meet strict new HSBC standards, including those where we had concerns in relation to tax compliance.”

As a result of that refocusing, HSBC’s Swiss private bank cut its client base by almost 70 percent since 2007, the bank told ICIJ.

A former IT employee of the Swiss unit, Hervé Falciani, provided the information to the French government, which then shared the data with the U.S. and other countries. French newspaper LeMonde obtained the information as well, sharing it with ICIJ, the consortium said. Falciani claims he is a whistleblower attempting to help governments fight tax evasion, but he is facing charges in Switzerland for industrial espionage and violating secrecy laws, Deutsche Welle reported.