Barclays has suspended six traders in connection with foreign exchange trading, sources with knowledge of the situation told CNBC.
Barclays declined to comment on the report, which comes after the Financial Times reported that RBS had suspended two traders in its foreign exchange division amid an ongoing probe.
(Read more: Banks brace for billion-dollar forex probe )
In its third-quarter earnings on Friday, RBS said that investigations relating to foreign exchange trading activities was a possible factor that could affect future results. It added that it was reviewing its forex trading procedures.
Barclays - along with UBS and Deutsche Bank - has already said it is in the early stages of reviewing its trading practices after being contacted by regulators about the fixing of foreign exchange.
Regulators launched a formal investigation into the market after media reports back in June highlighted alleged wrongdoing in foreign exchange trading.
(Read More: Forex market is 'wild west' as abuse probes begin )
The U.S. Justice Department, the U.K.'s Financial Conduct Authority (FCA), Switzerland's Financial Market Supervisory Authority, the Monetary Authority of Singapore and the Hong Kong Monetary Authority have all confirmed their involvement in the probe.
Every day, $5.3 trillion is traded in foreign exchange markets, according to the Bank of International Settlements, with around 41 percent of trades being processed through sales desks in the United Kingdom and 18 percent in the U.S. Deutsche Bank is the world's leading foreign exchange house, according to a Euromoney, with 15.18 percent. Second-placed Citi has a market share of 14.9 percent with Barclays and UBS just behind.
image: © Elliot Brown