The blast in the Zaporizhzhia region of southern Ukraine killed a cafe owner who was registered to run in elections seen as an attempt to legitimize Moscow’s illegal annexation of the area.

Evidence was growing on Friday that there was an explosion at the Kakhovka dam in southern Ukraine around the time it collapsed, according to Ukrainian and U.S. intelligence reports and seismic data from Norway.

Russian soldiers are standing at the checkpoints, preventing (rescuers) from approaching the most-affected areas and taking away the boats,” said one volunteer.

A U.S. official said American spy satellites detected an explosion at Ukraine's Kakhovka dam just before it collapsed and unleashed a torrent of flood water into surrounding areas this week, the New York Times reported on Friday.