A coalition of civil liberties groups and members of Congress are calling on President Obama to urgently review a controversial executive order being used by the National Security Agency to conduct mass surveillance.

Executive Order 12333, a Reagan-era authority, allows the NSA to covertly sweep up vast amounts of private data from overseas communication networks with no court oversight. Last week, The Intercept revealed how 12333 underpins a secret search engine the NSA built to share more than 850 billion records on phone calls, emails, cellphone locations, and internet chats with other U.S. government agencies, including domestic law enforcement. The search system, named ICREACH, contains information on the private communications of foreigners as well as, it appears, millions of Americans not accused of any wrongdoing.

Now, more than 40 organizations and rights groups – including Amnesty International, Human Rights Watch, and the American Civil Liberties Union – are calling on Obama and his surveillance review panel to ensure there is no “disproportionate or unnecessary collection” taking place under 12333.

In a letter to the President, dated 29 August and released on Tuesday, the groups say that the surveillance undermines “the fundamental rights of internet users everywhere” and demand that secret legal opinions or interpretations that relate to 12333 be declassified by the government. The letter states:

We, the undersigned former government officials, organizations, and members of Congress, write to express our concerns about the U.S. government’s surveillance activities conducted under the authority  of Executive Order 12333. Many involve communications that are protected by the U.S. Constitution,  and all implicate international human rights law, including the International Covenant on Civil and  Political Rights, to which the United States is a party. These activities undermine the fundamental rights of internet users everywhere.

The effort to rein in the surveillance is being led by digital rights group Access, which has enlisted the support of Representatives John Conyers (D-Mich.), Alan Grayson (D-Fla.), Rush Holt (D-N.J.), and Zoe Lofgren (D-Calif.). The Federal Trade Commission’s former Chief Technologist Ed Felton also co-signed the letter alongside two former State Department officials, Ian Schuler and John Tye.

In July, Tye was responsible for focusing public attention on 12333 when he wrote an op-ed for the Washington Post revealing that he had blown the whistle on the order while working for the State Department. The executive order as it is used today, Tye said, “threatens our democracy” because it can be used by the NSA to “incidentally” sweep up communications on Americans from foreign networks without any warrant and with minimal congressional scrutiny.

In his op-ed, Tye did not detail any specific classified programs that had caused him concern while inside the government. But recent disclosures from documents leaked by NSA whistleblower Edward Snowden – such as details about the vast ICREACH search engine – offer an insight into why he may have been alarmed, and have helped galvanize a growing campaign to limit the scope of 12333 surveillance operations.

“Revelations, such as that about ICREACH, have definitively helped raise the level of awareness of and opposition to the Executive Order, which helped bring this effort together,” Amie Stepanovich, senior policy counsel at Access, told The Intercept. “I think the breadth of signers on this letter shows an increasing consensus that reform is absolutely necessary.”