SIM card maker Gemalto says probe into hack by NSA, British spies finds no massive theft

A Dutch SIM-maker allegedly targeted by British and U.S. spying agencies says it believes there was a hacking operation, but it didn't result in a massive privacy leak.

Netherlands-based Gemalto, a maker of SIM cards used in mobile phones and credit cards, said Wednesday that an internal investigation "gives us reasonable grounds to believe" an operation by the U.S. National Security Agency and its British counterpart "probably happened."

The operation was reported last week on the website The Intercept using documents supplied by Edward Snowden.

Gemalto, a supplier to major mobile phone operators including AT &T, T-Mobile, Verizon and Sprint, says the attacks in 2010 and 2011 "only breached its office networks and could not have resulted in a massive theft of SIM encryption keys."