WASHINGTON (AP):

The pursuit of hackers who audaciously stole and published credit reports for Michelle Obama, the attorney general, FBI director and other United States (US) politicians and celebrities criss-crossed continents and included a San Francisco-based Internet company, Cloudflare, The Associated Press has learned.

The sensational crime caught the attention of Congress and President Barack Obama, who said "we should not be surprised".

Obama said he could not confirm that the First Lady's credit report was published earlier this week on a Russian website, along with what appeared to be the credit reports of nearly two dozen others, including Republican presidential candidate Mitt Romney, Donald Trump and celebrities Britney Spears, Jay Z, Beyoncé and Tiger Woods.

Perhaps in a show of defiance as the FBI, Secret Service and the Los Angeles Police Department coordinated efforts to investigate the security breach, the website added late Wednesday what it said was the credit report of disgraced Pennsylvania football coach Jerry Sandusky.

PERSISTENT THREAT

If accurate, as widely suspected, the leaked records put each victim at significant risk of identity theft.

Included in the reports are social security numbers, dates of birth and a list of previous home addresses. The records also include such personal information as the First Lady's monthly payments on a student loan 10 years ago and that she once held a Banana Republic credit card.

The president said determined hackers are a persistent threat.

"We should not be surprised that if you've got hackers who want to dig in and devote a lot of resources, that they can access people's private information," Obama told ABC News in an interview aired Wednesday. "It is a big problem."

Obama added: "It would not shock me if some information among people who presumably have pretty good safeguards against it, still gets out. That's part of the reason why we've got to continually improve what we do and coordinate between public and private sectors to make sure that people's information is safe."

On Capitol Hill, the chairman of the House Judiciary Committee cited the breach Wednesday at a congressional hearing about the government prosecuting hackers.

Bob Goodlatte, Republican, Vancouver, said the leaks of financial information was "just the beginning of the problem" when it comes to the vulnerability of US computer networks. Goodlatte said the US has billions of dollars at stake, as foreign hackers try to steal sensitive information from businesses.

"The truth is that all citizens are vulnerable to these kinds of cyberattacks," Goodlatte said.

A spokesman for one of the largest US credit bureaus, Tim Klein of Equifax, said an initial investigation showed that the hackers accessed the credit bureau's system by correctly entering personal details about their victims to impersonate them and generate the credit reports.

Representatives for Experian, Equifax and TransUnion have all said they were cooperating with the US criminal investigation being conducted by the FBI and Secret Service.

The FBI in San Francisco declined to tell AP whether investigators have contacted Cloudflare to review payments or communications that had been used to set up the service.

Social Security numbers posted on Jay-Z, Mel Gibson and others matched records in public databases. The numbers can be used to steal a person's identity and open credit accounts in their name.