Evidence suggests the Ukrainian dam collapsed due to a controlled explosion set off inside the structure. An international investigative group says it's 'highly likely' Russian forces were behind the attack.

• A critical dam in southern Ukraine collapsed on the early morning of June 6, displacing thousands.
• Ukraine and Russia have so far blamed each other for the attack.

The collapse of a major dam in southern Ukraine most likely occurred through a controlled explosion from within the structure, evidence reported by The New York Times suggests.

The Kakhovka hydroelectric dam, which is located in the Russian-controlled Kherson region, collapsed on the early morning of June 6, unleashing about 4.5 cubic miles of water from its reservoir into the Dnipro River and displacing thousands of surrounding residents from their homes.

Russia has pointed to the damages the dam has faced throughout the war to suggest the structure collapsed on its own and to discredit claims that its forces were responsible for any attack.

But experts told the Times the dam was built to withstand external damages, and the most likely cause was a large explosion detonated at a vulnerable spot of its foundation — a small passageway that runs through a large concrete block that is part of the dam also called the gallery.

"If your objective is to destroy the dam itself, a large explosion would be required," Michael W. West, a geotechnical and geological engineer, told The Times. "The gallery is an ideal place to put that explosive charge."

Ihor Strelets, who was in charge of water resources for the Dnipro River from 2005 to 2018, also told the publication that he believed an explosion in the gallery destroyed part of the dam.

In addition, seismic sensors in Ukraine and Romania picked up signs of a large explosion near the time of the dam's collapse, according to the report. The Times reported that a US intelligence satellite also captured infrared heat signals in the area just before the dam fell apart.

Ukraine and Russia have quickly blamed each other for the dam's destruction.

A senior US military official told the Times that Russian operatives were most likely behind the attack.

The Mobile Justice Team, an arm of the Atrocity Crimes Advisory Group, which is an international investigatory body comprised of the US, the European Union, and the UK, issued a report on Thursday concluding that it is "highly likely Russian forces deliberately destroyed" the Kakhovka dam, CNBC reported.