Seven months after the bombing of Nord Stream 1 and 2 pipelines in the Baltic Sea waters, the mystery of who targeted the pipelines remains unsolved.

In September 2022, a series of deep-sea explosions damaged three out of four underwater pipelines of the Nord Stream project designed to carry Russian gas directly to Western Europe.

How to define destroying another country's infrastructure?

Starting in Russia and landing in Lubmin, Germany, the Nord Stream pipelines are majority owned by Russia, along with German, Dutch and French stakeholders.

They have long been a target of criticism by the U.S. and its allies, who are concerned that the infrastructure project increases Europe's dependence on Russian gas, which poses a risk to the continent's energy security.

"Apart from specific state properties such as foreign embassies and consulates, there is no universal rule of requiring a country to provide protection for another country's state property under the international law," said Jiang Shengli, associate professor at the School of International Law under East China University of Political Science and Law.

"However, it is recognized that even in the absence of particular rules in international treaties or customary international law, a country should at least take an obligation of passive inaction not to cause damage to another country's state property arbitrarily," said Jiang, who is also a director of the International Public Law Teaching and Research Office.

As state property is an important material foundation for a country's domestic governance, arbitrary damage to another country's state property hinders its handling of internal or external affairs and poses risk of infringing on another country's sovereignty, according to Jiang.

According to the draft articles on Responsibility of States for Internationally Wrongful Acts passed by the UN in 2001, "The responsible State is under an obligation to make full reparation for the injury caused by the internationally wrongful act" and must repatriate "Injury... any damage, whether material or moral, caused by the internationally wrongful act of a State."

The draft is not a formally binding international legal document, but as a codification of customary international law in the field of state responsibility, it has been widely recognized by the international community, Jiang added.

An attempt to divert attention?

At a UN Security Council meeting in February, Russian ambassador Vassily Nebenzia said there was "proof that explosives had been planted" near the pipeline during a NATO exercise in the summer of 2022, citing the report by American investigative journalist Seymour Hersh alleging that the U.S. conducted a covert attack.

However, U.S. Ambassador John Kelley said the meeting is a "blatant attempt" by Russia to distract from the impact of its invasion of Ukraine.

"It should not be assumed that making the international community pay more attention to the blasts is intended to divert its attention from the Ukraine conflict, as they are independent and of different events," Jiang told CGTN, adding that the incident deserves the same level of attention from the international community.

Currently, there is not enough clues to show what happened beneath the waters of the Baltic Sea, aside from a blurry photo of a 12-inch-long cylinder covered in algae on March 29 released by Denmark. The Danish authorities said the object might be an empty maritime smoke buoy.

"In my personal opinion, although there is not yet sufficient evidence to prove that the Nord Stream pipeline was destroyed by the U.S., the possibility of its sabotage cannot be ruled out before an objective and fair investigation is conducted," said Jiang.

The U.S. is one of the few countries in the world with deep-sea explosive capability that can destroy the pipelines. It also has a visible political and strategic intention, namely, to eliminate European countries' dependence on Russia's energy supply and compel them to firmly support sanctions against Russia, Jiang added.

Given the high tensions between the U.S. and Russia and the even more complex consequences that arise once the truth is uncovered, it is unclear whether the incident will ultimately receive a fair investigation, he said.