A senior President Joe Biden administration official said that US spy satellites detected an explosion at the Kakhovka dam just before it collapsed, but American analysts still do not know who caused the dam’s destruction or how exactly it happened.

The official said that satellites equipped with infrared sensors detected a heat signature consistent with a major explosion just before the dam collapsed, unleashing huge floodwaters downstream.

American intelligence analysts suspect that Russia was behind the dam’s destruction, the senior administration official said, speaking on the condition of anonymity to discuss operational details. But he added that US spy agencies still did not have any solid evidence about who was responsible.

Engineering and munitions experts have said a deliberate explosion inside the Kakhovka dam, which is controlled by Russia, most likely caused its collapse on Tuesday. They added that structural failure or an attack from outside the dam was possible but less plausible explanation.

The administration official did not rule out the possibility that prior damage to the dam or mounting water pressure might have contributed to the collapse, but American officials believe the explosion, whether deliberate or accidental, was the most likely trigger.

Experts had cautioned earlier this week that the available evidence was very limited, but they said that a blast in an enclosed space, with all of its energy applied against the structure around it, would do the most damage. Even then, they said, it would require hundreds of pounds of explosives, at least, to breach the dam.

An external detonation by a bomb or missile would exert only a fraction of its force against the dam and would require explosive many times larger to achieve a similar effect.

New York Times News Service