The EU is “trampling over Palestinian rights” and risks breaching international law, over an energy deal signed with Israel to bring more gas to Europe, a campaign group has said.

A report by Global Witness shared exclusively with the Guardian concludes that the EU could be “complicit in breaches of international law” over a 2022 energy deal linked to gas imports from a pipeline said to traverse Palestinian waters. The NGO has called on the EU to cancel all gas imports linked to the East Mediterranean Gas (EMG) pipeline and terminate the 2022 deal, which was also signed with Egypt.

The spotlight on the EU’s energy ties with its Middle Eastern ally comes after the European Commission concluded there were “indications” Israel was in breach of human rights obligations over the catastrophic humanitarian consequences of its war in Gaza and rampant Israeli settler violence in the West Bank.

While the EU is facing growing calls to cancel completely or in part its trade and cooperation agreement with Israel, Europe’s energy relationship with Israel has attracted little attention, notably a gas deal that appears to have been automatically rolled over last month.

The European Commission signed a memorandum of understanding (MoU) with Israel and Egypt in June 2022, with the aim of “enabling a stable delivery of natural gas to the EU”. It was sealed a few months after Russia’s full-scale invasion of Ukraine, as the EU was racing to secure alternative energy suppliers.

Global Witness contends that the EMG pipeline, which runs parallel to the Gaza coastline, plays an important role in enabling gas exports to Europe from Egypt. The 56-mile (90km) pipeline transports gas from Ashkelon in Israel to Arish in Egypt, where it is then processed into liquefied natural gas for export, including to Europe.

The NGO claims the EMG pipeline runs through Palestinian waters. Its work is guided by a legal opinion drafted pro bono by two barristers at the London-based Garden Court Chambers.

Zehrah Hasan, a human rights barrister and co-author of the opinion, told the Guardian: “Israel unilaterally constructed and operated the pipeline without the consent of the Palestinian authorities, and Palestine hasn’t been afforded the opportunity to stipulate any financial, environmental or regulatory conditions.

“So in our view that was another example of how Israel is very likely breaching international law in its continued denial of Palestinian sovereignty.

“There’s a very strong basis to contend that the EU is likely in violation of customary international law and EU law by signing and continuing the MoU.”

Hasan has a Palestinian flag on her social media profile, but is said to have carried out the work in line with her regulatory duties to act independently.

Israel has previously described Palestine’s claimed maritime zone as “legally invalid”. Israel’s mission to the EU in Brussels and foreign ministry in Jerusalem did not respond to requests for comment. Nor did Palestine’s mission to the EU.

Gleider Hernández, a professor of public international law at KU Leuven, who was not involved in the study, told the Guardian that he believed Global Witness “arrive at what is probably the correct conclusion” about a risk of breaching international law.

He cautioned, however, that the analysis relied on Palestine’s statehood being established. Irrespective of Palestinian statehood, he pointed to Israel’s obligations as an occupying power under the fourth Geneva convention not to exploit the territory purely for its own benefit, ignoring the inhabitants.

He said: “In building a pipeline in the area concerned, Israel is probably committing an unlawful act … And then the question becomes … is the EU breaching one of its obligations vis-à-vis international law by having signed the MoU. And there, I think so … Even though the gas would not be directed to Israeli settlements in the West Bank, it would constitute a sort of toleration of Israel’s misuse of its prerogatives as the occupying power.”

The law professor also pointed to the landmark opinion from the UN’s international court of justice (ICJ) in July 2024 that ordered Israel to end its occupation of Palestinian territories as soon as possible. In that non-binding opinion, the court called on other countries not to recognise the occupation as lawful or assist it.

“Thus the construction of [the pipeline] very well may be a breach of the obligations identified by the court also with respect to third actors such as the EU,” he said.

The situation, he added, “did not become unlawful in 2024”, but “the international court simply recognised the situation of illegality that had been in existence for some time before then”.

As to whether the EU should have signed the agreement in 2022, he said: “I would have said don’t do it.”

Barry Andrews, an Irish centrist MEP, who chairs the European parliament’s development committee, told the Guardian via email: “Given Israel’s persistent illegal occupation of Palestine, the legal warnings of the international court of justice in its advisory opinion issued last year and the ongoing genocide in Gaza, the EU risks being in breach of its international legal obligations by continuing with this energy cooperation.”

He called for an urgent review of the MoU “with a view to suspension, reaffirming our commitment to upholding international law and human rights”.

Sarah Biermann Becker, a senior investigator at Global Witness, said: “Since Russia’s invasion of Ukraine, the EU has tried to position itself as a defender of human rights, but its continued business with Israel exposes a deplorable double standard.”

She accused the EU of “pursuing a gas deal that tramples over Palestinian rights” and which “effectively helps bankroll Israel’s genocide on Gaza”.

The ICJ is considering the charge that Israel has committed genocide, and the UN’s special rapporteur on human rights in the occupied Palestinian territories, Francesca Albanese, has used the term since January 2024.

The criticism of the energy deal comes before an EU meeting on 15 July when foreign ministers expect an update from the EU’s foreign policy chief, Kaja Kallas, on her talks with Israel’s government. Kallas said she would talk to her Israeli counterpart about the findings of the unprecedented review of the EU-Israel association agreement.

Since the EU found “indications” of human rights violations, Israel has ramped up its offensive, adding to the death toll that now stands at more than 57,000 people, mostly civilians. The retaliatory war was launched after Hamas militant attacks on 7 October 2023 killed 1,219 people and took 251 hostage. Since then nearly the entire 2.3 million population of Gaza has been displaced and the territory reduced to ruin.

The MoU was due to be extended automatically in mid-June this year. The European Commission did not respond to repeated questions about the agreement.

Announcing the trilateral deal in June 2022, the European Commission president, Ursula von der Leyen, said she was “grateful that Israel will increase its supply of energy to the EU”.

Israel’s then energy minister, Karine Elharrar, hailed the agreement as historic and said it enabled Israel “for the first time to export Israeli natural gas to Europe”. It was, she said, “another step towards positioning Israel as a natural gas superpower” and “a diplomatic lever”.

Between 2020 and 2024 nearly 9bn cubic metres of LNG was exported from Egypt to Europe, according to Global Witness analysis of Rystad Energy data. Spain, Italy and France were the top importers of the gas, buying around half, worth $9bn. The campaign group argues that most Israeli gas to Egypt goes via the EMG pipeline, as it is the most direct route with the biggest capacity.

While it is not possible to trace the exact molecules from Israel to the EU, Global Witness contends that additional gas from Israel to Egypt enables exports to the EU. The MoU shows an intention, the NGO states, “to further support and enable the export of Israeli gas to the EU”.

Gas flows have continued largely uninterrupted during the massive upsurge in violence. Israel suspended operations at two gas fields supplying Egypt and Jordan last month, hours after launching surprise airstrikes against Iran. Operations were resumed nearly two weeks later.