Executives with Europe's biggest bank, HSBC, were subjected to a humiliating onslaught from US senators on Tuesday over revelations that staff at its global subsidiaries laundered billions of dollars for drug cartels, terrorists and pariah states.

Lawmakers hammered the British-based bank over the scandal, demanding to know how and why its affiliates had exposed it to the proceeds of drug trafficking and terrorist financing in a "pervasively polluted" culture that persisted for years.

A report compiled for the committee detailed how HSBC's subsidiaries transported billions of dollars of cash in armoured vehicles, cleared suspicious travellers' cheques worth billions, and allowed Mexican drug lords buy to planes with money laundered through Cayman Islands accounts.

Other subsidiaries moved money from Iran, Syria and other countries on US sanctions lists, and helped a Saudi bank linked to al-Qaida to shift money to the US.