NEW YORK (AFP) ― Investigators were digging Thursday to find who initiated and what was taken in an apparent intense hacker effort this month to penetrate the systems of U.S. banks including JPMorgan Chase.

The Federal Bureau of Investigation acknowledged that it and the Secret Service were “working to determine the scope of recently reported cyberattacks against several American financial institutions.”

The cursory statement, and one from JPMorgan assuring that it has tough defenses against cyberthreats, did not confirm multiple reports that the bank and several other Wall Street giants have been targeted, possibly by Russian hackers.

And none of the other large U.S. banks would say if they were on the receiving end of any particularly malicious attempt to penetrate their systems.

But JPMorgan and computer security experts said online attacks were frequent and rising.

“Companies of our size unfortunately experience cyber attacks nearly every day. We have multiple layers of defense to counteract any threats and constantly monitor fraud levels,” said a JPMorgan spokesperson.

Candid Wueest, a threat researcher with Symantec Security Response, told AFP that such attacks are multiplying rapidly.

Around the world, he said, “we had last year an increase in data breaches of 62 percent,” with most in the U.S.

That includes more than 265 data breaches confirmed in the last 12 months, “and probably a lot that have not been publicly named.”

Key targets are large U.S. companies, like banks and retailers with a lot of data records on consumers, including credit-card numbers.

In December 2013 retail giant Target lost possibly 100 million client records to hackers, an embarrassment that cost it sales and, ultimately, forced the chief executive to step down.