NEW YORK — The European Court of Human Rights in Strasbourg will hear a landmark case on surveillance Tuesday as part of a challenge to the lawfulness of the U.K.’s surveillance laws and its intelligence agencies’ mass surveillance practices.

The case was brought by the American Civil Liberties Union, Amnesty International, Liberty, Privacy International, and 10 other human rights and journalism groups — as well as two individuals — based in Europe, Africa, Asia, and the Americas.

The court enforces the European Convention on Human Rights, a treaty ratified by 47 nations. Its judgments are legally binding and its rulings help shape the interpretation of human rights law throughout the world.

The case is the latest stage in a protracted effort from the organizations to challenge the British government’s wide-ranging surveillance powers following the revelations by NSA whistleblower Edward Snowden.

In 2013, Snowden revealed how the U.K.’s intelligence agency GCHQ was secretly intercepting and processing millions of private communications of ordinary people on a daily basis and sharing data with the NSA, as well as other countries’ intelligence agencies.

The case is an appeal of a December 2014 decision by the Investigatory Powers Tribunal, the British court which has jurisdiction over GCHQ, MI5, and MI6. The tribunal ruled that these practices may in principle comply with the U.K.’s human rights obligations.

The parties point out that the U.K.’s surveillance laws and practices affect the privacy and other rights of millions of people around the world, in part because major internet cables run to and from British territory. They have also raised concerns about the risks to confidential sources who often speak out and the impact on the work of human rights groups.

As an illustration of these concerns, this case brings to the European Court of Human Rights’ attention a finding by the Investigatory Powers Tribunal that the communications of Amnesty International and the South Africa-based Legal Resources Centre were unlawfully spied upon by U.K. intelligence agencies.

The case is also expected to have wide-ranging implications for last year’s controversial Investigatory Powers Act, which changed the U.K.’s legal framework governing surveillance matters, allowing for further blanket surveillance.

In addition to the indiscriminate interception of communications, the Investigatory Powers Act allows security agencies to hack computers and other electronic devices on a large scale, harvesting potentially huge amounts of personal data from individuals who are not suspected of any criminal behavior.

The following organizations that brought the case had these comments:

Ashley Gorski, ACLU staff attorney, said: “Not only does this suit have significant implications for the rights of non-Americans, but it matters for Americans as well. Should the court find the U.K.’s mass surveillance unlawful, it would send the powerful message that similar mass spying programs like the NSA’s are fundamentally incompatible with human rights. These bulk spying programs invade the privacy of countless people without suspicion of wrongdoing, and they undermine the foundations of a free society.”

Martha Spurrier, director of Liberty, said: “Our organizations exist to stand up for people and challenge abuse of power. We work with whistleblowers, victims, lawyers, journalists, and campaigners around the world, so confidentiality and protection of our sources is vital. The U.K. government’s vast, cross-border mass surveillance regime, which lets it access millions of people’s communications every day, has made those protections meaningless.

“Losing our privacy is the gateway to losing everything that keeps us free — the right to protest, to a fair trial, to practice our religion, to think and speak freely. No country that deploys industrial-scale state surveillance has ever remained a rights-respecting democracy. We now look to the court to uphold our rights where our government has failed to do so.”

Nick Williams, Amnesty International’s senior legal counsel, said: “This case is a watershed moment for people’s privacy and freedom of expression across the world. The case concerns the U.K., but its significance is global. By bringing together human rights defenders and journalists from four different continents, it serves to highlight the dangers mass surveillance poses to the vital work of countless organizations and to individuals who expose human rights abuses and defend those at risk.”

Scarlet Kim, Privacy International’s legal officer, said: “For years, the U.K. government has been intercepting the private communications and data of millions of people around the world. At the same time, it can access similarly enormous troves of information intercepted by the U.S. government. These practices are unlawful and violate the fundamental rights of individuals across the world, assailing privacy and chilling thought and speech. They are incompatible with open and democratic societies. We call on the European Court of Human Rights to reject them by finding bulk surveillance incompatible with the rights to privacy and freedom of expression enshrined in the European Convention on Human Rights.”

The case brings together three separate challenges from the following groups and individuals: the ACLU, Amnesty International, Bytes for All, the Canadian Civil Liberties Association, the Egyptian Initiative for Personal Rights, the Hungarian Civil Liberties Union, the Irish Council for Civil Liberties, the Legal Resources Centre, Liberty and Privacy International; Big Brother Watch, Open Rights Group, English Pen and Dr. Constanze Kurz; The Bureau of Investigative Journalism and Alice Ross.