Hackers who compromised gigabytes of data at JPMorgan Chase & Co. earlier this year also attempted without success to breach the computer networks of other financial institutions, a report said Monday, citing people with knowledge of the investigation. The hack at JPMorgan Chase was first disclosed in August.

Last month, several financial institutions were asked by federal officials to check for indications of a cyberattack that resulted in the breach of personal information of millions of JPMorgan customers, the Wall Street Journal reported, adding that many financial institutions said that they had seen traffic to their networks from suspect IP addresses, but did not believe their systems had been hacked.

While it is still unknown which financial institutions were targeted by the hackers, there are also disagreements about the extent of the hackers’ access to the U.S. financial sector, the Journal reported, citing federal officials.

“It is like the equivalent of a robber walking around your house and looking for an open window and they walk away,” Bill Nelson, CEO of the Financial Services Information Sharing and Analysis Center, told the Journal.

The hack at JPMorgan Chase affected about 76 million households worldwide, the bank said last week while disclosing details of the information theft, which included names, phone numbers and email addresses of customers. The bank also said that the hackers could not gather details such as account numbers, passwords, Social Security numbers and dates of birth.

Last month, Keith Alexander, former director of the National Security Agency, or NSA, said that the hack could have been backed by a rival nation's government and should serve as a warning to other U.S. financial institutions.

“How would you shake the United States back? Attack a bank in cyberspace,” Alexander told Bloomberg, in an interview, adding that the hackers had sent a message: "‘You’re vulnerable.’”