BNP Paribas SA is facing fines of about $2 billion as well as criminal charges for violating US economic sanctions against several countries including Iran, according to people with direct knowledge of the matter, part of an accelerating crackdown by American authorities that has caused upheaval among European banks.

An internal probe by France's largest listed bank found that it breached sanctions against Iran and tried to cover up these transactions by altering trades to remove coding that would identify their origin, a process known as stripping, said one of the people. US authorities are weighing criminal charges also against individual employees, the person said.