Early this week, three separate leaks were discovered in two giant natural gas pipelines from Russia. The pipelines were filled with the fuel, and the ruptures produced gas bubbles a half-mile wide that rose to the surface of the Baltic Sea, near the Danish island of Bornholm.

Explosions had been detected nearby just before the leaks occurred, and European governments have not yet identified the cause of the leaks in the pipelines, known as Nord Stream 1 and Nord Stream 2. Political leaders in Europe and the United States have suggested that the incident was an act of sabotage.

Speculation has pointed to Russia, whose state-controlled energy company, Gazprom, is the main owner of the pipelines. A spokesperson for President Vladimir Putin of Russia, Dmitry Peskov, dismissed allegations of Russian involvement as "stupid” and pointed a finger at the United States.