NEW YORK (AFP) ― Citigroup and JPMorgan Chase said Friday they have been approached by U.S. and foreign authorities investigating possible manipulation in the foreign exchange markets.

In filings with the Securities and Exchange Commission, both U.S. banks reported having received queries on the issue, days after Barclays Bank, Deutsche Bank, UBS and Royal Bank of Scotland also acknowledged being under investigation over foreign exchange market issues.

“Government agencies in the U.S. and other jurisdictions are conducting investigations or making inquiries regarding trading on the foreign exchange markets,” Citi said.

“Citigroup has received requests for information and is cooperating with the investigations and inquiries and responding to the requests.”

JPMorgan said it had received information requests from “various government authorities” regarding its foreign exchange trading business.

“These investigations are in the early stages and the firm is cooperating with the relevant authorities,” it said.

Neither bank gave any other information on the direction of the probe.

On Thursday Barclays Bank reported it had received enquiries on its foreign exchange trading covering several years through August 2013. Before that, the other banks acknowledged they had been contacted.

Britain’s Financial Conduct Authority said last month that alongside several other agencies it was investigating a number of firms relating to trading on the foreign exchange market.

Swiss regulators have said as well that they are investigating forex market manipulation.

The banking sector has already been shaken by a rigging scandal related to the Libor, a benchmark rate for lending between banks that also determines numerous financial and interest rate contracts around the world.

That scandal has already resulted in more than $3.5 billion in government settlements with financial institutions, as well as ongoing criminal prosecutions of several traders involved.