WASHINGTON – The Justice Department says the British bank HSBC violated the Bank Secrecy Act in connection with the laundering of money from narcotics drug traffickers in Mexico.

In court papers filed Tuesday, the federal government said the case against HSBC is related to the laundering of proceeds from narcotics trafficking via the Black Market Peso Exchange — a method by which money launderers convert cash narcotics dollars into Colombian pesos.

The government also alleges that HSBC intentionally allowed prohibited transactions with Iran, Libya, Sudan and Burma. The bank also facilitated transactions with Cuba in violation of the Trading With the Enemy Act, according to the documents.

The documents in federal court in Brooklyn say the prohibited transactions with Iran, Libya, Sudan and Burma took place from 2001 through 2006.

The government’s allegations come as HSBC says it has agreed to pay $1.9 billion to settle the U.S. money-laundering probe. The move avoids a legal battle that could further savage the bank’s reputation and undermine confidence in the global banking system.