Key US lawmakers stepped up angry calls for formal probes, including an FBI investigation, into whether the phone-hacking firestorm at Rupert Murdoch's media empire had reached US shores.
House Homeland Security Committee Chairman Peter King, a Republican, urged Federal Bureau of Investigation Director Robert Mueller to look into whether News Corp. employees targeted the phone records of September 11 victims.
"The 9/11 families have suffered egregiously, but unfortunately they remain vulnerable against such unjustifiable parasitic strains. We can spare no effort or expense in continuing our support for them," he said in a letter to Mueller.
"Any person found guilty of this purported conduct should receive the harshest sanctions available under law," said King, who represents a New York district that was home to more than 150 of those killed in the attacks.
Earlier, Democratic Senators Jay Rockefeller and Barbara Boxer urged Attorney General Eric Holder and Mary Schapiro, chief of the Wall Street watchdog Securities and Exchange Commission, to investigate whether US laws were broken.
The lawmakers, who chair the US Senate's Commerce and Environment and Public Works committees, respectively, also cited the reports that Murdoch employees targeted the phones of victims of the September 11, 2001 terrorist strikes.
"The reported allegations against News Corporation are very serious, indicate a pattern of illegal activity, and involve thousands of potential victims," the lawmakers said in a letter to Holder and Schapiro.
"It is important to ensure that no United States laws were broken and no United States citizens were victimized," the senators said.
They also pointed to charges that employees of Murdoch's News Corp. -- a US-based firm -- had bribed British police as part of the hacking scandal, saying that could violate a US law, the Foreign Corrupt Practices Act (FCPA).
Democratic Senator Robert Menendez wrote Holder separately to urge a probe into charges by a British lawmaker that Murdoch employees had hacked into the phones of victims of the terrorist strikes ten years ago.
"The US government must ensure that victims in the United States have not been subjected to illegal and unconscionable actions by these newspapers seeking to exploit information about their personal tragedies for profit," he said.
And Democratic Senator Frank Lautenberg also wrote to Holder and Schapiro to urge an investigation and said "further investigation may reveal that current reports only scratch the surface of the problem at News Corporation."
The Justice Department declined to comment on the growing congressional chorus of outrage, with a spokeswoman telling AFP: "We don't typically confirm or deny investigations even if one were to happen."
White House spokesman Jay Carney said the issue was "not on our radar" even though "we're aware of it."
But Rockefeller, a former Senate intelligence committee chairman, told reporters his "bet" was that an investigation would turn up "criminal stuff" and predicted: "This will be a huge issue."
Rockefeller had called Tuesday for "the appropriate agencies" of the US government to probe whether alleged hacking by members of Murdoch's media empire extended to US citizens and warned of "severe" consequences.
Under British government pressure, Murdoch dramatically dropped his bid for control of pay-TV giant BSkyB Wednesday.
Hours before Britain's three main parties were set to back an extraordinary parliamentary vote calling for the withdrawal of the bid, Murdoch's US-based News Corp. said it was now "too difficult to progress in this climate."
British Prime Minister David Cameron welcomed the news, saying the Australian-born tycoon should focus on cleaning up his business after the scandal which forced the closure of the News of the World tabloid on Sunday.» In parliament Wednesday Cameron also announced the details of a full public inquiry into phone hacking, which he said would also include links between politicians and the press.
After decades as Britain's political kingmaker, Murdoch has seen his empire threatened by a wave of public outrage over the hacking of voicemails belonging to people including a murdered girl and the families of dead troops.
In the United States, Murdoch's Fox News Channel is seen by many Democrats as a tool of their Republican rivals, while the network denies any bias.