U.S. and U.K. authorities have fined the Royal Bank of Scotland more than $610 million for its role in the manipulation of a key global interest rate.

RBS is the third major bank caught up in an international scandal over banks' setting the rate. The London interbank offered rate, or LIBOR, provides the basis for trillions of dollars in contracts around the world, including mortgages, bonds and consumer loans.

The U.S. Commodity Futures Trading Commission says RBS submitted false data on interest rates to benefit its trading positions.

U.S. and UK regulators fined RBS more than $460 million for rate-rigging. Meanwhile, a unit of RBS agreed to plead guilty in a Department of Justice investigation. It accepted a penalty of $150 million and will co-operate in its probe.